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SOME  VIEWS  OF  OUR 
NEW  BUILDING 


SCIENTIFIC  INSTRUMENT  WORKS 

l-e-knott^pparatus  co. 

OUR  BUILDING  IS  OF  MOST  MODERN  CONSTRUCTION  OF 
REINFORCED  CONCRETE,  FIREPROOF,  WELL-LIGHTED  AND 
WELL -VENTILATED.  IT  IS  AN  IDEAL  BUILDING  FOR  THE 
MANUFACTURE  OF  SCIENTIFIC  INSTRUMENTS. 


L.  E.  KNOTT  APPARATUS  COMPANY 

CAMBRIDGE  STATION  A  BOSTON,  MASS. 


L.  E.  KNOTT  APPARATUS  COMPANY,  BOSTON 


OUR  LARGE  AND  WELL -LIGHTED  SALESROOM 
GIVES  US  AN  UNUSUAL  OPPORTUNITY  TO  DIS¬ 
PLAY  THE  VARIOUS  INSTRUMENTS  OF  OUR 
MANUFACTURE.  THE  VIEW  ABOVE  SHOWS 
THE  MASSACHUSETTS  INSTITUTE  OF  TECH¬ 
NOLOGY  BEYOND. 


L.  E.  KNOTT  APPARATUS  COMPANY,  BOSTON 


WE  EXTEND  TO  ALL  PERSONS  WHO  MAY 
FIND  THEMSELVES  IN  BOSTON  OR  VICINITY 
A  CORDIAL  INVITATION  TO  VISIT  US.  WE  ARE 
LOCATED  FOUR  MINUTES’  WALK  WEST  OF  THE 
KENDALL  SQUARE  STATION  OF  THE  CAM¬ 
BRIDGE  SUBWAY.  (THREE  MINUTES  FROM 
PARK  STREET.) 


L.  E.  KNOTT  APPARATUS  COMPANY,  BOSTON 


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A  Catalogue 

of 

Scientific  Instruments 


Catalogue  21 


i 


L.  E.  Knott  Apparatus  Company 

AMES  AND  AMHERST  STREETS 

(Cambridge  A  Station) 

BOSTON 


ELEAZAR  CATE 

President 

ROLAND  E.  STEVENS 

Vice-President 


ARTHUR  W.  HALL 

Treasurer 

WARREN  L.  MAXCY 

Secretary 


4  # 

WE  have  copyrighted  this  entire  book  for  the  purpose  of 
protecting  ourselves  against  the  unauthorized  use  of  our 
text  or  original  illustrations  by  dealers  who  seek  to  create 
the  impression  that  their  goods  are  the  same  as  the  special  apparatus 
which  we  manufacture  or  control. 

The  trade  is  notified  that  no  use  of  our  illustrations  or  descrip¬ 
tions  will  be  permitted,  and  that  we  shall  take  prompt  action  in  the 
case  of  piracy. 


Copyright,  1916,  by 
The  L.  E.  Knott  Apparatus  Co. 


N  A.  LINDSEY  &  CO.,  PRINTERS,  BOSTON,  MASS. 


THE  GETTY  CENTER 

LIBRARY 


PREFACE 


WE  offer  in  the  following  pages  a  series  of  scientific  instruments  and  a  list  of 
physical  apparatus  which  will  be  found  adequate  for  the  study  of  Physics  in  the 
most  advanced  laboratory.  All  instructors  in  science  will  recall  that  we  are  by 
direct  descent  the  oldest  apparatus  house  in  this  country,  dating  back  to  1854.  We  still 
have  with  us  men  who  have  worked  under  and  were  intimately  connected  with  such  men 
as  E.  S.  Ritchie,  A.  P.  Gage,  and  A.  E.  Dolbear.  Many  will  recall  that  it  was  Mr.  E.  S. 
Ritchie  whom  Professor  Tyndall  selected  to  assist  him  during  his  American  lectures. 

The  number  of  this  catalogue  indicates  the  number  of  years  that  the  L.  E.  Knott 
Apparatus  Company,  under  its  present  name,  has  been  in  business.  During  this  time 
it  has  doubtless  equipped  more  laboratories  and  furnished  more  material  to  colleges  and 
schools  than  any  other  house  of  its  line.  We  therefore  feel  that  we  are  peculiarly  well 
fitted  to  offer  a  catalogue  such  as  this.  We  ask  your  consideration  of  the  following  pages. 

Under  each  subject  we  have  aimed  to  include  only  those  pieces  best  suited  for  the 
particular  experiment  and  demonstration.  In  making  this  selection  from  our  complete 
line  we  have  found  that  it  requires  even  greater  judgment  to  determine  what  to  omit  than 
it  does  to  determine  what  to  include,  but  unnecessary  duplication  has  been  carefully 
avoided.  We  realize  that  the  instructor  whose  duty  it  is  to  equip  or  improve  a  laboratory 
should  buy  only  the  best  and  at  the  same  time  strive  to  make  his  appropriation  go  as  far  as 
possible. 

A  large  proportion  of  the  articles  offered  have  been  designed  and  developed  in  our 
own  laboratory  under  the  supervision  of  men  whose  training  and  experience  have  well 
fitted  them  for  the  task.  In  making  the  selection  we  have  been  guided  by  numerous  sug¬ 
gestions  received  from  our  customers,  an  obligation  which  we  are  pleased  at  this  time 
to  acknowledge,  with  the  hope  that  all  of  our  customers  will  feel  it  an  obligation  as  well 
as  a  pleasure  to  favor  us  with  any  further  suggestions  which  their  experience  develops. 

Such  a  complete  line  of  educational  instruments  as  we  here  list  could  hardly  have 
been  offered  at  this  time  had  it  not  been  for  the  greatly  improved  and  well-nigh  perfect 
facilities  which  our  new  reinforced  concrete  building  has  placed  at  our  disposal.  At  first 
the  European  war  caused  some  forebodings  as  to  its  effect  on  the  completeness  of  our  line, 
but  the  advantage  offered  by  our  new  factory  has  dispelled  all  fears  of  this  nature. 

We  wish  to  emphasize  the  fact  that  in  the  compiling  of  this  catalogue  we  have  endeav¬ 
ored  to  make  it  more  than  a  price-list.  The  arrangement,  we  believe,  will  be  found  to  have 
been  made  on  a  scientific  basis,  each  instrument  being  classified  and  appearing  in  its  proper 
place.  We  have  embodied  in  our  descriptions  many  valuable  suggestions  concerning  the 
use  of  the  apparatus  on  the  lecture  table  and  in  the  laboratory.  The  illustrations  are 
original,  prepared  from  photographs  taken  from  the  completed  instrument  itself. 


DIRECTIONS  AND  TERMS 


THIS  CATALOGUE  SUPERSEDES  AND  DISPLACES  ALL  PREVIOUS 

EDITIONS 


CORRESPONDENCE:  —  Persons  writing  to  us  should  use  an  official  letter-head  when¬ 
ever  possible.  If  such  stationery  is  not  available,  kindly  advise  what  institution  you 
are  connected  with  and  the  position  you  hold. 

ORDERS:  —  Order  blanks  will  be  furnished  to  prospective  buyers  upon  request.  When 
making  out  your  orders,  specify  the  catalogue  number  and  the  edition,  with  sufficient 
•  description  to  indicate  clearly  the  article  desired.  This  will  prevent  errors  which  might 
occur  where  the  catalogue  number  alone  is  given,  or  where  the  description  alone  is 
given. 

SHIPPING:  —  Specify  clearly  the  place  to  which  the  goods  are  to  be  consigned,  giving 
the  County,  City  and  State  address.  Indicate  your  preference  as  to  whether  you 
desire  to  have  the  goods  sent  by  freight,  express  or  mail.  It  should  be  borne  in  mind 
that  express  rates  are  much  higher  than  freight,  and  customers  at  a  distance  should  give 
instructions  to  ship  by  express  only  when  they  are  prepared  to  pay  the  additional 
charges  for  quick  delivery.  Where  no  instructions  are  given,  we  exercise  our  best 
judgment  as  to  the  manner  and  route  of  shipment.  Unless  the  customer  has  a  prefer¬ 
ence,  we  suggest  that  the  matter  be'left  to  our  experienced  judgment.  Small  articles 
which  we  are  instructed  to  send  by  mail  are  consigned  at  the  customer’s  risk,  but  will 
be  registered  if  requested.  We  charge  for  boxing  and  casing  at  cost. 

REMITTANCES:  —  Our  terms  are  net  thirty  days.  We  allow  a  cash  discount  of  1  per 
cent,  from  the  face  of  the  bill  if  the  check  is  sent  to  us  within  ten  days  from  the  date 
of  invoice.  Interest  at  the  usual  rate  is  charged  for  overdue  accounts.  All  remit¬ 
tances  should  be  made  in  checks  payable  through  the  New  York  or  Boston  Clearing 
House.  On  checks  or  drafts  payable  at  other  points,  the  proper  amount  to  cover  the 
exchange  should  be  added.  School  Warrants  should  be  registered  and  if  it  be  known 
that  no  money  is  immediately  available  for  payment,  please  advise  us  when  funds  will 
be  provided.  If  local  banks  are  prepared  to  purchase  these  warrants  at  par,  the  names 
of  such  banks  should  accompany  the  warrant. 

RETURNS:  —  If  for  any  reason  it  is  desirable  to  return  goods,  kindly  advise  us  by  mail 
concerning  the  conditions  so  that  no  misunderstanding  may  arise.  We  are  always 
glad  to  accommodate  but  we  cannot  accept  or  give  credit  for  goods  which  are  returned 
without  previous  arrangement  having  been  made. 

REPAIRS:  —  If  goods  are  sent  to  us  for  repair,  see  that  the  case  is  properly  marked,  giving 
the  name  of  the  sender.  Send  us  a  letter  at  the  same  time  stating  what  you  are  re¬ 
turning  and  what  you  wish  to  have  done  to  it. 


LABORATORY 

FURNITURE 


SINCE  1896  we  have  maintained  a  special  department  for  the  critical 
investigation  and  study  of  laboratory  and  lecture-room  needs.  It  has 
been  the  duty  of  this  department  to  design  and  manufacture  both 
the  laboratory  and  lecture-room  tables  and  the  special  and  distinctive  general 
fittings  which  are  necessary  in  order  to  secure  the  best  possible  facilities  for 
high-grade  science  work. 

That  this  service  has  been  appreciated  is  evidenced  by  the  constantly  in¬ 
creasing  business  which  this  department  has  been  called  upon  to  handle. 

It  is  a  source  of  great  satisfaction  to  us  that  architects,  school  boards  and 
superintendents  of  schools  are  more  and  more  availing  themselves  of  the  techni-. 
cal  experience  of  this  department,  appreciating  as  they  do  that  two  decades  of 
constant  application  to  this  work  have  put  us  in  position  to  render  valuable 
assistance. 

On  the  following  pages  we  list  a  few  of  the  standard  designs  which  have 
proven  most  generally  serviceable.  These  designs  will  serve  to  illustrate  the 
high  character  of  our  laboratory  furniture: 

t 

1st.  Each  piece  is  designed  with  a  complete  knowledge  of  the 
conditions  under  which  it  is  to  be  used. 

2nd.  Full  consideration  has  been  given  to  the  fact  that  a  labo¬ 
ratory  table  becomes  a  permanent  part  of  the  building 
and  hence  should  be  as  rigid  and  as  substantial  as  the 
building  itself. 

3rd.  Material,  finish,  and  workmanship  should  be  of  the  best, 
to  insure  durability  equal  to  the  life  of  the  building. 

The  services  of  this  department  are  freely  offered  to  those  who  are  plan¬ 
ning  new  laboratories. 


2 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  » 


STANDARD  PHYSICS  TABLE 


No.  1-100 


1-100  PHYSICS  TABLE  with  FIXED  UPRIGHT  and  ADJUSTABLE  CROSS-BAR.  This  table 

has  been  so  extensively  used  for  the  last  fifteen  years  that  it  is  considered  the  Standard 
Physics  Laboratory  Table.  The  body  is  made  of  selected  kiln-dried  ash,  oil  and  wax 
finish,  presenting  a  handsome  finish,  accentuating  the  grain  of  the  wood.  The  top  is 
built  up  of  selected,  straight-grained,  kiln-dried  strips,  machined,  matched  and  joined 
in  such  a  manner  as  to  prevent  warping.  It  is  finished  a  durable  black  acid-proof  finish. 
Uprights  and  cross-bar  are  of  ash,  inches  by  3  inches,  finished  to  match  body,  cross¬ 
bar  being  held  by  the  Knott  Special  Three-Part  Clamp  which  readily  allows  adjustment 
without  binding  and  which  will  hold  the  bar  firmly  in  any  desired  position. 

This  table  is  6  feet  long,  4  feet  wide  and  34  inches  high.  It  is  equipped  with  four  drawers, 
two  on  each  side. 

Each,  f.  o.  b.  Factory,  $29.75 

We  are  prepared  to  furnish  tables  of  any  desired  finish  to  match  furniture  already  in  the 
building,  and,  if  the  order  is  sufficiently  large,  this  can  be  done  without  extra  charge. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


3 


PHYSICS  TABLE 


No.  1-120 


1-120  PHYSICS  TABLE.  This  table  has  found  considerable  favor  in  Physics  Laboratories 
from  the  fact  that  the  rods  and  clamps  with  which  laboratories  are  so  universally  equipped 
may  be  utilized  for  the  uprights  and  cross-bar.  The  detachable  feature,  leaving  clear 
the  whole  top  of  the  table,  is  a  distinct  advantage. 

This  table  is  of  the  same  high  quality  as  No.  1-100.  It  is  six  feet  long,  four  feet  wide, 
thirty-four  inches  high.  It  is  not  provided  with  drawers,  as  in  laboratories  provided 
with  ample  storage  facilities  they  may  be  considered  unessential. 

With  each  table  accessories  for  uprights  and  cross-bar  attachments  are  furnished  as  follows: 

Two  5-1150  “Harcourt”  Universal  Basic  Clamps  “B.” 

Two  5-20e  Threaded  Rods,  19  millimeters  diameter,  for  uprights. 

Two  5-765  Right  Angle  V  Clamps. 

One  5-40c  Support  Rod  for  Cross-Bar,  19  millimeters  diameter. 

Table  complete  as  above,  f.  o.  b.  Factory,  $29.75 

1-125  PHYSICS  TABLE, — same  table  as  No.  1-120,  but  furnished  without  uprights  and  cross¬ 
bar,  as  they  are  not  required  where  a  laboratory  already  has  such  an  equipment. 

Table  only,  f.  o.  b  Factory,  $21.00 

We  are  prepared  to  furnish  tables  of  any  desired  finish  to  match  furniture  already  in  the 
building,  and,  if  the  order  is  sufficiently  large,  this  can  be  done  without  extra  charge. 


4 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


STANDARD  LECTURE  TABLE 


No.  1-150 


1-150  COMBINATION  LECTURE  TABLE  for  either  PHYSICS  or  CHEMISTRY  LECTURE 
ROOM.  This  table  has  the  distinctive  qualities  of  all  our  laboratory  furniture.  The  body 
is  made  of  selected  kiln-dried  ash,  oil  and  wax  finish.  Top  is  built  up  from  selected 
narrow,  straight-grained,  kiln-dried  strips,  machined,  matched  and  joined  in  such  a 
manner  as  to  prevent  warping.  It  has  a  durable  black  acid-proof  finish. 

It  is  furnished  equipped  with  plumbing  to  the  floor  line  for  both  gas  and  water  and  supplied 
with  the  Knott  special  goose-neck  water  faucet  which  carries  three  attachments,  - 
one  for  small  rubber  hose,  one  for  large,  and  one  for  attaching  an  aspirator.  It  has, 
in  addition,  one  four-way  Knott  Turret  for  gas  supply  and  a  Special  Gas  Cock  with 
lever  handle  and  long  serrated  ends. 

It  is  equipped,  also,  with  two  No.  5-274  nickel-plated  Flush  Sockets,  two  No.  5-20e  Sup¬ 
port  Rods,  two  No.  5-765  Right  Angle  Clamps  and  No.  5-40b  Support  Rod  for  Cross- 
Bar. 

The  design  of  this  desk  is  such  as  to  afford  best  facilities  for  Lecture  Table  Demonstration. 
Top  is  supplied  with  lead-lined  pneumatic  sink,  18  inches  square  by  16  inches  deep,  with 
a  shelf  8  inches  wide  placed  6  inches  from  the  top.  The  front  and  ends  are  paneled  and 
back  is  equipped  with  three  large  and  two  small  drawers,  four  open  shelves  and  com¬ 
modious  cupboard.  ' 

This  table  is  8  feet  long,  3  feet  wide  and  34  inches  high. 

Each,  f.  o.  b.  Factory,  $103.00 

We  are  prepared  to  furnish  tables  of  any  desired  finish  to  match  furniture  already  in  the 
building,  and,  if  the  order  is  sufficiently  large,  this  can  be  done  without  extra  charge. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


5 


INSTRUCTORS  TABLE 


No.  1-200 

1-200  INSTRUCTOR’S  LABORATORY  TABLE  for  small  lecture  room.  The  body  of  this  table 
is  of  ash,  oil  and  wax  finish.  The  top  is  built  up  from  straight-grained,  kiln-dried  strips 
with  special  black  acid-proof  finish. 

It  is  furnished  equipped  with  plumbing  to  the  floor  line  for  gas  and  water  and  supplied  with 
the  Knott  special  goose-neck  faucet  which  carries  three  attachments,  —  one  for  small 
and  one  for  large  rubber  tubing  connections,  and  one  for  attaching  an  aspirator,  a  two- 
way  turret  for  gas  connections  with  a  special  lever-handle  gas  cock  with  long  serrated 
ends.  Set  into  the  top  of  the  table  is  a  lead-lined  sink,  16X10X9  inches  deep. 

The  top  is  further  equipped  with  three  No.  5-270  and  two  No.  5-274  Flush  Plates  for 
the  three  No.  5-10e  and  two  No.  5-20e  Support  Rods,  one  No.  5-40a  Support  Rod  for 
Cross-Bar  and  two  No.  6-765  Right  Angle  V  Clamps.  Electrical  Connections  illustrated 
are  furnished  only  on  application  and  at  an  extra  charge. 

This  table  is  designed  to  offer  the  best  possible  facilities  in  the  smallest  space.  The 
front  and  ends  are  paneled;  the  back  has  five  drawers  and  commodious  cupboard  space. 

The  table  is  5  feet  long  by  2x/i  feet  wide  by  34  feet  high. 

Each,  f.  o.  b.  Factory,  $67.50 

We  are  prepared  to  furnish  tables  of  any  desired  finish  to  match  furniture  already  in  the 
building,  and,  if  the  order  is  sufficiently  large,  this  can  be  done  without  extra  charge. 


# 


6 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


APPARATUS  CABINET 


An  experience  extending  over  two  decades  has  demonstrated  positively  to  us  that  education- 
al  institutions  in  need  of  adequate  and  serviceable  storage  space  for  any  of  the  branches  of  science 
have  felt  a  far  greater  satisfaction  in  purchasing  cabinets  built  especially  to  fit  and  meet  individual 
conditions. 

We  have  the  best  of  facilities  for  building  such  furniture  to  order. 

% 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


7 


LOOSE-LEAF  FILING  CABINET 


No.  1-660 


1-650  LOOSE-LEAF  CABINET  for  storing  and  filing  loose-leaf  material  of  all  kinds. 

This  cabinet,  originally  designed  to  fulfil  the  demand  for  storage  and  filing  facilities  for 
Loose-Leaf  Note-Book  material,  has  found  a  place  of  equal  value  in  the  offices  of  school 
superintendents  and  principals.  Its  adaptability  to  the  filing  of  school  records  for  instant 
reference,  is  unsurpassed  by  any  system  of  filing.  By  opening  the  two  doors,  the  entire 
fifty-six  compartments,  all  legibly  numbered,  become  at  once  available.  Each  compart¬ 
ment  has  a  capacity  of  from  150  to  200  separate  sheets  of  paper,  with  four  wide  com¬ 
partments  at  the  bottom,  each  capable  of  holding  1,000  or  more  sheets. 

The  convenience  of  this  cabinet  in  the  storing  of  Direction  Sheets  of  Loose-Leaf  Note- 
Books  is  at  once  apparent,  and  Educational  Institutions  using  a  Loose-Leaf  System  of 
Instruction  will  readily  realize  the  necessity  of  ample  storage,  indexed  for  ready  reference. 

The  cabinet  is  substantially  built  of  ash  with  paneled  sides  and  doors,  heavy  moulding  at 
top  and  bottom.  It  is  carried  in  stock  attractively  finished  in  antique  oak. 

Dimensions  over  all,  —  height  40  inches,  width  inches,  depth  13^  inches. 


Each,  f.  o.b.  Factory,  $19.75 


We  are  prepared  to  furnish  cabinets  of  any  desired  finish  to  match  furniture  already  in 
the  building,  and,  if  the  order  is  sufficiently  large,  this  can  be  done  without  extra  charge. 


8 


L.  E.,  KNOTT  APPARATUS  CO.,  BOSTJON 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


9 


THE  KNOTT 

SCIENCE  LABORATORY  FITTINGS 


Twenty  years  ago  when  we,  as  pioneers  in  building  laboratory  furniture,  required  gas  and  water  fixtures  adapted 
particularly  to  science  laboratory  requirements,  it  was  with  considerable  surprise  that  we  found  that  there  were  no 
commercial  fittings  adapted  to  such  special  and  exacting  conditions.  After  a  most  critical  investigation  and  study 
of  laboratory  and  lecture-room  needs,  we  designed  the  following  fittings  which  have  found  universal  favor.  They 
are  used  exclusively  on  all  of  our  laboratory  furniture. 


No.  1-760 


No.  1-800 


No.  1-726  No.  1-700 


No.  1-801 


KNOTT’S  GAS  COCKS 


No.  1-802 


The  Knott  Gas  Cocks  are  of  brass.  The  nipples  are  long  and  with  five  sharp  serrations  which  make  it  easy 
to  slip  on  rubber  tubing,  but  impossible  to  pull  it  off  accidentally.  Adjustment  is  secured  by  means  of  a  lever  handle. 

1-700  KNOTT’S  LEVER  HANDLE  GAS  COCK,  M  inch  I.  P . $0.66 

1-710  KNOTT’S  SINGLE  GAS  TURRET,  one  gas  cock .  1.46 

1-716  KNOTT’S  TWO-WAY  GAS  TURRET,  two  gas  cocks  .  .  1.86 

1-720  KNOTT’S  THREE-WAY  GAS  TURRET,  three  gas  cocks .  2.26 

1-726  KNOTT’S  FOUR-WAY  GAS  TURRET,  four  gas  cocks .  2.66 

1-760  THE  KNOTT  MOUNTED  FOUR-WAY  GAS  TURRET.  The  use  of  this  design  obviates  all 
necessity  of  cutting  a  table  top.  It  is  connected  by  rubber  tubing  to  a  supply  cock  left  at  the 
floor  line  or  above  the  table .  4.60 


WATER  FAUCETS 

These  faucets  are  of  heavy  brass  with  full  nickel  finish.  Three  interchangeable  attachments  are  provided, — 
two  for  connecting  rubber  tubing  from  to  %  inch  in  diameter,  the  third,  a  regular  hose  bib  coupling  for  attaching 
an  aspirator.  Adjustment  is  secured  by  a  large  wheel  handle  which  in  actual  use  has  been  found  the  best  for  student 
use. 

1-800  KNOTT’S  WHEEL  HANDLE  INTERCHANGEABLE  NOZZLE  STRAIGHT  WATER  FAUCET, 


inch  I.  P . $2.90 

1-801  - ,  BENT  WATER  FAUCET  y2  inch  I.  P .  3.60 

1-802  - ,  GOOSE-NECK  WATER  FAUCET,  inch  I.  P .  6.00 


10 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


LABORATORY  SUPPORT  RODS 


Our  Rods  are  of  cold  rolled  Bessemer  steel,  copper-plated  and  heavily  nickeled,  thus  ob¬ 
viating  the  possibility  of  rust  deterioration.  They  are  straight,  of  uniform  diameter,  machine 
threaded,  and  shoulders  faced  to  attain  a  perfect  junction  when  used  on  our  bases  and  flush 
plates. 


No.  5-40 


M 


R 


« 

Nos.  6-10  to  6-56 


AT  US 


3 > 


ASS 

t 


6-10  SUPPORT  RODS,  10  millimeter  diameter,  threaded  to  fit  any  hole  tapped  34  X  20. 

abode 
Length .  10  15  20  30  40  centimeters. 

Each . $0.16  .18  .20  .26  .29 

5- 16  SUPPORT  RODS,  13  millimeter  diameter,  threaded  to  fit  any  hole  tapped  Yi  X  16. 

d<  b  c  d  6 

Length .  20  40  60  80  100  centimeters. 

Each . $0.26  .35  .48  .60  .80 

6- 20  SUPPORT  RODS,  19  millimeter  diameter,  threaded  to  fit  any  hole  tapped  34  X  12. 

a  b  c  d  e  f 

Length .  30  40  60  80  100  120  centimeters. 

Each . $0.42  .62  .70  .88  1.00  1.36 

6-30  SUPPORT  RODS,  30  millimeter  diameter,  threaded  to  fit  any  hole  tapped  %  X  10. 

3,  t)  C  d  6 

Length .  60  80  100  120  160  centimeters. 

Each . $1.66  1.90  2.30  2.46  3.36 

6—40  SUPPORT  RODS,  for  use  as  horizontal  rods,  19  millimeter  diameter,  ends  rounded. 

a  b  c 

Length .  100  125  185  centimeters. 

Each . $1.10  1.36  2.20 

6-60  SQUARE  SUPPORT  RODS,  19  millimeters  square,  one  end  turned  to  19  millimeter  diameter,  and  threaded 
to  fit  any  hole  tapped  Y  X  12.  No.  6-60  d-f  are  most  frequently  used  as  bed-rods  of  optical  benches. 

a  b  c  d  e  f 

Length .  40  60  80  100  120  200  centimeters. 

Each . $1.16  1.66  1.96  2.30  3.40  4.46 

6-66  SQUARE  SUPPORT  RODS,  same  as  Nos.  6-50d  and  6-50f,  but  graduated  to  millimeters.  A  few  of  these 
rods  are  valuable  additions  to  every  laboratory,  as  they  may  be  used  in  many  ways  besides  as  bed-rods  for 
optical  benches,  —  the  purpose  for  which  they  were  originally  intended. 

a  b 

Length .  100  200  centimeters. 

Each . $6.60  10.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


ii 


Nos.  5-100  to  5-215 


TRIPOD  BASES 

Our  line  of  Tripod  Bases  is  scientifically  designed  to  give  the  greatest  possible  degree  of  stability  without  oc¬ 
cupying  too  much  room  on  the  working  table.  The  nine  sizes  of  the  series  fill  all  needs  from  the  standpoint  of  size, 
stability,  and  the  use  of  all  the  rods  listed  on  the  previous  page.  Each  tripod  is  faced  top  and  bottom  that  shoulders 
of  Support  Rods  may  make  close  junction  and  may  be  in  true  perpendicular  with  the  plane  of  the  base.  All  holes 
are  machine  drilled  and  threaded. 

Our  castings  are  uniformly  smooth,  thus  offering  a  good  surface  for  a  strikingly  smooth  and  beautiful  finish. 
All  sizes  are  carried  in  stock  with  and  without  leveling  screws. 

5-100  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  6  centimeters,  tapped  34  X  20  to  take  any  10 


millimeter  rod .  $0.84 

5-101  “  “  Same  as  above,  without  leveling  screws .  .26 

5- 104  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  8  centimeters,  tapped  34  X  20  to  take  any  10 

millimeter  rod . 98 

6- 105  “  “  Same  as  above,  without  leveling  screws . 28 

5-110  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  10  centimeters,  tapped  34  X  20  to  take  any  10 

millimeter  rod .  1.10 

5-111  “  “  Same  as  above,  without  leveling  screws . 48 

5- 114  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  12  centimeters,  tapped  34  X  20  to  take  any  10 

millimeter  rod .  1.20 

6- 115  “  “  Same  as  above,  without  leveling  screws . 68 

5-120  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  14  centimeters,  tapped  24  X  16  to  take  any  13 

millimeter  rod .  1.35 

5- 125  “  “  Same  as  above,  without  leveling  screws . 72 

6- 130  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  18  centimeters,  tapped  24  X  16  to  take  any  13 

millimeter  rod .  1.85 

5- 136  “  “  Same  as  above,  without  leveling  screws .  94 

6- 140  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  18  centimeters,  tapped  34  X  12  to  take  any  19 

millimeter  rod . ' .  1.86 

6-146  “  “  Same  as  above,  without  leveling  screws . 94 

6-150  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  21  centimeters,  tapped  34  X  12  to  take  any  19 

millimeter  rod  ....  2.15 

5-165  “  “  Same  as  above,  without  leveling  screws .  1.10 

5- 160  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  26  centimeters,  tapped  34  X  12  to  take  any  19 

millimeter  rod .  3.15 

6- 165  “  “  Same  as  above,  without  leveling  screws .  1.65 

6-170  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  26  centimeters,  tapped  24  X  10  to  take  any  30 

millimeter  rod .  3.15 

6-176  “  “  Same  as  above,  without  leveling  screws .  1.65 

6-180  TRIPOD  BASE,  with  leveling  screws,  length  of  leg  50  centimeters,  tapped  24  X  10  to  take  any  30 

millimeter  rod .  6.90 

6-186  “  “  Same  as  above,  without  leveling  screws .  4.80 


ROUND  BASES 

In  the  design  of  our  Round  Bases  we  have  followed  the  same  rules  for  stability  as  in  Tripod  Bases  listed  above. 
Our  Castings  are  uniformly  smooth,  bases  faced  top  and  bottom,  machine  drilled  and  tapped,  handsomely  finished. 


6-200  ROUND  BASE,  diameter  8  centimeters,  tapped  J4  X  20  to  take  any  10  millimeter  rod  . $0.20 

6-206  - ,  diameter  10  centimeters,  tapped  34  X  20  to  take  any  10  millimeter  rod . 22 

6-210  - ,  diameter  12  centimeters,  tapped  24  X  16  to  take  any  13  millimeter  rod . 36 

6-216  - ,  diameter  15  centimeters,  tapped  24  X  16  to  take  any  13  millimeter  rod . 60 


12 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


6-240  “INSTITUTE”  H-BASE.  The  distinctive  shape  of  this  base  affords  a  stability  equal  to  that  of  a 
round  base  and  in  addition  enables  the  experimenter  to  place  a  jar  or  other  apparatus  within  one 
inch  of  the  support  rod.  The  curvature  is  somewhat  greater  than  that  of  a  4  X  5  battery  jar. 
Threaded  34  X  20  to  take  any  of  our  10  mm.  rods . $0.60 


No.  6-242 


6-242  “HARCOURT”  SPECIAL  H-BASE.  This  base  is  more  massive  than 
above  and  is  threaded  34  X  12  to  take  any  of  our  19  mm.  rods. 
Curvature  somewhat  greater  than  that  of  a  6  X  8  battery  jar. 

We  utilize  this  base  in  a  number  of  our  instruments.  See  Nos. 

43-270,  62-10,  63-200,  53-206,  53-215,  62-50,  92-76,  etc.,  etc.  $1.00 


THE  KNOTT  ADJUSTABLE  ECCENTRIC  LEVELING  BASES 

The  design  of  our  Adjustable  Eccentric  Leveling  Base  is  the  outgrowth  of  a  demand  for  a  base  of  great  stability, 
yet  one  which  will  permit  placing  the  base  close  to  other  apparatus  on  the  lecture  table.  The  telescoping  extension 
legs  give  wide  range  of  usefulness.  With  the  two  sizes  we  are  able  to  meet  the  stability  of  any  round  bases  from 
1134  to  32  inches  in  diameter.  The  eccentric  discs  on  the  end  of  each  extension  leg  give  a  positive  and  easily  operated 
level  adjustment. 


No.  6-250 

Patent  Pending 


No.  6-252 

Patent  Pending 


6-250  “THE  KNOTT”  ADJUSTABLE  ECCENTRIC  LEVELING  BASE,  adjustable  to  cover  an  area 


from  1134  to  1834  inches  in  diameter . $2.35 

6-252  - ,  adjustable  to  cover  an  area  from  1834  to  32  inches  in  diameter .  3.66 


No.  6-260 

6-260  ANDREW’S  PLATE  BASE.  There  has  been  considerable  demand  for  a  base  of  the  right  dimen¬ 
sions  to  carry  a  number  of  support  rods  so  that  apparatus  might  be  set  up  on  a  lecture  table  and 
moved  bodily  from  place  to  place.  The  base  which  we  list  was  designed  by  Mr.  Calvin  H. 
Andrews  of  the  High  School  of  Commerce,  Worcester,  Mass.,  and  is  the  most  satisfactory  design 
which  we  have  yet  seen. 

It  is  provided  with  five  holes  on  a  line  through  the  center  of  the  base,  one  threaded  %-16  and  four 
34-12,  properly  located  for  most  convenient  use.  The  base  is  massive  in  construction,  size 
10  X  18  inches.  We  recommend  two  of  these  bases  for  each  lecture  table . Each,  $4.90 


Nos.  5-270  to  6-274 


FLUSH  PLATES,  for  inserting  in  any  laboratory  table  flush  with  the  top.  These  plates  are  heavily  nickel-plated 
and  polished.  When  fitted  to  a  table  and  screwed  into  place,  they  offer  a  support  amply  rigid  for  all  laboratory  oper¬ 


ations. 

6-270  FLUSH  PLATE,  tapped  34  X  20  to  take  any  10-millimeter  rod . $0.35 

6-272  - ,  tapped  34  X  16  to  take  any  13-millimeter  rod . 46 

6-274  - ,  tapped  34  X  12  to  take  any  19-millimeter  rod . 70 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


13 


6-350 


6-360 


No.  6-350 


No.  6-365 


MISCELLANEOUS 

SUPPORTS 

TABLE  CLAMP  for  attaching  to  edge  of 
table  to  hold  round  or  square  rods  in 
either  horizontal  or  vertical  position.  V’s 
and  extra  broad  flange  are  carefully 
milled.  To  be  used  on  table  7.5  centi¬ 
meters  or  less  thick . $1.40 

TABLE  CLAMP  for  attaching  to  edge  of 
table  to  hold  round  or  square  rods  in  ver¬ 
tical  position.  This  design  obviates  dan¬ 
ger  of  injury  to  table,  yet  at  same  time, 
from  its  structure  offers  a  rigid  support. 

May  be  used  with  our  Interlocking  T- 
Beam  Attachments,  “Series  B.”  Tapped 

X  12  to  take  19-millimeter  rod  .  .  .  1.90 


No.  5-360 


No.  5-375  No.  5-386  No.  6-375 


5-365  TABLE  CLAMP,  similar  to  above  but  less  massive  and  cannot  be  used  with  our  Interlocking  T-Beam 

Attachments,  “Series  B.”  Tapped  %  X  16  to  take  any  of  our  13  mm.  rods . $  .85 

5-366  - ,  tapped  X  12  to  take  any  of  our  19  mm.  rods .  1.00 

5- 375  END  SUPPORTS  for  supporting  rods  in  a  horizontal  position,  originally  designed  for  holding  bed-rod 

of  optical  benches.  Extreme  care  is  exercised  in  machining  these  supports  so  that  they  will  meet 

all  requirements . Each  .55 

6- 386  SECONDARY  SUPPORTS  for  attaching  to  round  or  square  rods  to  support  objects  in  horizontal 

position.  Convenient  for  holding  telescopes;  also  for  levels  in  level-testing  experiments  ,  Each  .42 


Nos.  6-400  to  6-416 

5-400  STAND  TUBE,  into  which  a  13-millimeter  rod  may  be  telescoped  and  clamped  at  desired  heights 
within  range  of  20  centimeters,  —  the  height  of  the  tube.  In  conjunction  with  a  base  tapped  %  X  16 
and  with  STAND  TOPS  Nos.  6-475  and  5-480,  will  make  an  adjustable  table  support  ....  $1.26 


5-405  - ,  same  as  above,  but  30  centimeters  long .  1.46 

5-410  STAND  TUBE  for  use  as  in  No.  6-400,  to  take  19- millimeter  rod,  and  will  fit  any  base  tapped  ^  X  12. 

Length  30  centimeters.  Will  require  No.  6-486  or  6-490  .  2.00 

5-415  - ,  same  as  above,  but  40  centimeters  long .  2.25 


14 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


Nos.  5-430  to  5-440 


No.  5-450 


5-430  EXTENSION  CLAMP,  for  holding  two  rods  adjustably  parallel  to  each  other.  For  two  19  millimeter 


rods  .  . $0.65 

5- 435  - ,  same  as  above,  but  for  two  13  millimeter  rods . ; . 64 

4 

6- 440  - ,  same  as  above,  but  for  two  10  millimeter  rods . 44 


5-450  V  OPENING  EXTENSION  CLAMP  for  holding  two  rods  adjustably  parallel  to  each  other.  This 
clamp  has  been  designed  to  obviate  the  inconveniences  of  the  old  form  with  parallel  holes  which 
must  be  attached  to  the  rod  by  placing  it  over  the  ends.  Our  new  design  for  use  with  10  to  19  milli¬ 
meter  rods  may  be  slipped  on  the  rod  and  clamped  by  the  nickel-plated  T  screw . 55 


Nos.  6-470  to  5-490 


5-470  STAND  TOP,  15  centimeters  diameter,  tapped  for 
use  with  any  10  millimeter  rod  threaded  ^  X  20. 
Frequently  used  in  conjunction  with  Stand  Tube 
No.  6-400  or  5—405,  and  a  suitable  base  to  form 
an  adjustable  table.  Made  of  three-ply  wood  to 
prevent  warping . 

5-476  STAND  TOP,  15  centimeters  in  diameter,  but  tapped 
to  receive  any  13  millimeter  rod  threaded  %  X  16 

5- 480  - ,  same  as  above,  but  20  centimeters  in  diameter 

6- 485  STAND  TOP,  20  centimeters  in  diameter,  but  tapped 

to  receive  any  19  millimeter  rod  threaded  }/%  X  12 

6-490  —  — ,  same  as  above,  but  30  centimeters  in  diameter. 


$0.98 

.98 

1.22 

1.44 

1.64 


6-610  ADJUSTABLE  LABORATORY  STAND  for  table  use.  This  stand  is  substantially  built  of  metal, 
with  three-ply  wood  top.  This  top  is  adjustable  in  height  from  the  minimum  height  of  40  centi¬ 
meters  to  a  maximum  of  70  centimeters. 

This  stand  will  be  found  of  great  convenience  on  the  lecture  table.  The  stand  being  heavy  and  the 
center  of  gravity  low,  the  top  may  be  clamped  as  any  table  top  and  a  system  of  rods  and  clamps 
utilized  to  gain  greater  latitude  and  adjustment . $  9.60 


■,  same  as  above,  top  adjustable  from  70  to  130  centimeters 


15.00 


8-511 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


15 


No.  6-515 


No.  6-51 5a 


No.  5-515b 


5-515  GEOMETRIC  STANDS,  for  blocking  up  apparatus.  Set  consists  of  six  tripods  fitting  into  each 
other,  the  uppermost  surmounted  by  neat  wooden  top  13  inches  in  diameter.  Top  alone  with  its 
leveling  screws  gives  an  adjustment  from  2%  inches,  the  minimum  height,  to  3  inches,  the  maxi¬ 
mum.  Each  tripod  varies  height  by  13^  inches.  Total  maximum  height  8)4  inches.  Per  Set  of  Six  $4.65 


6-515a  TRIPOD  WITH  WOOD  TOP,  and  LEVELING  SCREWS,  as  used  in  above . Each  2.25 

6-515b  TRIPOD  only,  as  used  in  above . Each  .60 


5-525  PLATFORM  for  10  millimeter  rod.  Made  of  cast  iron,  top  carefully  milled  true.  Top  7  X  8.5 


centimeters .  . $0.60 

5- 527  - ,  same  as  above,  for  19  millimeter  rod  . 60 

6- 530  - ,  same  as  above,  for  10  millimeter  rod,  top  8.5  X  11.5  centimeters . 76 

5- 535  -  ,  same  as  above,  for  13  millimeter  rod,  top  8.5  X  11.5  centimeters . 76 

6- 540  -  — ,  same  as  above,  for  13  millimeter  rod,  top  11.5  X  15.5  centimeters  . 94 

6-646  - ,  same  as  above,  for  19  millimeter  rod,  top  14.5  X  21.5  centimeters  .  1.60 


No.  5-670 

5-570  WALL  STAND,  of  general  utility  in  laboratory  practice.  Designed  to  be  placed  on  a  rail  fixed  to  the 
wall  or  laboratory  table.  Wood  plate,  30  centimeters  in  diameter,  oil  and  wax  finish,  mounted 
adjustably  on  19  millimeter  rod .  $12.50 


i6 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6-690 


No.  6-696 

Patent  Pending 


6-690  KNIFE  EDGE  BRACKET  for  attachment  to  the  side  of  a  room  as  a  knife  edge  support  for  a  rod 
in  Bending  Beam  experiments. 

This  bracket  is  made  of  cast  iron  from  a  pattern  of  our  own  design.  It  is  handsomely  japanned  and 

the  knife  edge  carefully  milled  true . . Each 

6-696  KNIFE  EDGE  CLAMP  for  attaching  to  the  edge  of  a  table  top  to  form  an  adjustable  support  for  a 
beam  in  Bending  Beam  experiments. 

This  clamp  is  one  of  our  T-Beam  Series  (see  No.  6—1060)  and  highly  recommended  for  the  universal 
adaptation  which  is  one  of  its  unique  features. 

Clamp  complete  as  illustrated  . 

6-1060  KNIFE  EDGE  CLAMP  ATTACHMENT  ONLY . .  .  . 

6-1000  “HARCOURT”  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A.” . 

6-696  KNIFE  EDGE  CLAMP  for  attaching  to  the  edge  of  a  table,  but  knife  edge  not  adjustable 


$0.60 


1.69 

.66 

.94 

.65 


No.  5-610 

6-610  LEVELING  SCREWS  for  use  in  sets  of  three  for  rapidly  leveling  a  plane  surface.  Made  entirely  of 
metal,  base  accurately  milled.  Adjustable  from  minimum  height  of  65  millimeters  to  90  millimeters. 

Per  set  of  three  .  .  1.40 


6-636 

6-636 

6-637 

6-638 

6-646 


6-646 

6-647 


Nos.  6-646  to  6-647 


COLLAR  for  allowing  a  clamped  rod  to  freely  revolve  and  yet  keeping  rod  at  height  fixed  by  position 

of  collar.  Designed  for  30  millimeter  rod . 

- ,  same  as  above  but  for  19  millimeter  rod  . 

- ,  same  as  above  but  for  13  millimeter  rod  . 

- ,  same  as  above  but  for  10  millimeter  rod  . 

HOOK  COLLAR  for  10  millimeter  rod.  The  addition  of  a  hook  to  a  collar  has  been  found  exceedingly 
useful  in  our  laboratory  work.  Its  use  as  a  support  may  be  noted  in  illustration  of  Nos.  27-290  and 
27-300.  It  may  readily  be  adapted  to  a  multitude  of  uses  when  a  system  of  Interchangeable 

Laboratory  Supports  is  a  part  of  the  school  equipment . Each 

- ,  same  as  above  but  for  13  millimeter  rod . Each 

- ,  same  as  above  but  for  19  millimeter  rod . Each 


$0.58 

.48 

.39 

.33 


.24 

.28 

.65 


No.  6-670 

RIGHT  ANGLE  PIECE  for  clamping  two  10  millimeter  rods  at  right  angles  to  each  other, 
nickel-plated  with  two  nickel-plated  T-screws . 


Neatly 


$0.50 


5-670 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


17 


CLAMPS 


Our  Clamps  are  designed  to  give  maximum  strength  at  stress  points  with  use  of  as  little 
metal  as  practical  to  preserve  symmetry.  All  our  clamps  are  ribbed  at  points  of  stress;  our  cast¬ 
ings  are  uniform  and  smooth,  thus  presenting  a  good  surface  for  a  smooth,  handsome,  and  durable 
finish;  all  parts  designed  to  be  at  right  angles  or  parallel  are  as  accurately  so  as  machinists’  skill 
can  produce.  As  jigs  and  standard  gauges  are  used  as  far  as  practicable,  each  lot  will  be  found 
uniform  in  dimensions.  All  holes  are  reamed  to  a  sliding  fit;  all  screws  are  heavily  nickel  plated 
and  of  size  proportional  to  size  of  clamp;  all  V’s  are  accurately  milled. 


No.  6-725 


No.  5-746 


No.  6-760 


No.  5-765 


No.  5-770 


No.  5-785 


No.  5-810 


No.  6-825 


6-725  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  planes  accurately  at  right  angles  to  each  other. 

V  opening  to  clamp  13  millimeter  rod,  hole  for  10  millimeter  rod . $0.46 

5- 730  - ,  same  as  above,  but  V  opening  to  clamp  19  millimeter  rod,  hole  for  13  millimeter  rod .  .66 

6- 736  - ,  for  use  in  holding  optical  bench  accessories.  V  opening  to  clamp  19  millimeter  rod,  hole  for 

13  millimeter  rod.  Central  (zero)  point  indicated .  .90 

6-746  RIGHT  ANGLE  CLAMP,  V  opening  to  clamp  30  millimeter  rod,  hole  19  millimeters .  .90 

5- 760  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  planes  accurately  at  right  angles  to  each  other. 

Two  V  openings  for  clamping  13  millimeter  rods .  .44 

6- 766  - ,  same  as  above,  but  with  two  V  openings  for  clamping  19  millimeter  rods .  .63 

6-770  “HARCOURT”  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  same  plane  at  right  angles  to 
each  other.  Two  V  openings  for  clamping  13  to  19  millimeter  rods,  one  accurately  perpendicular  to 


the  other. 

This  form  of  clamp  will  be  found  a  marked  improvement  over  types  on  the  market,  as  more  rapid 
changes  and  adjustments  are  possible.  Its  universal  adaptability  to  work  not  possible  with  old 
forms  is  readily  apparent .  .96 

6-786  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  same  plane  but  accurately  at  right  angles  to  each 

other.  V  opening  to  clamp  19  millimeter  rod,  tapped  x/i  X  20  to  receive  10  millimeter  rod  ...  .46 

6-790  - ,  same  as  above,  but  tapped  %  X  16  to  receive  13  millimeter  rod  .  .66 

5- 810  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  same  plane  but  at  right  angles  to  each  other.  V 

opening  to  clamp  to  19  millimeter  rod,  hole  10  millimeters.  Convenient  for  holding  accessories 
having  shank  10  millimeters  in  diameter .  .68 

6- 816  OPTICAL  BENCH  RIGHT  ANGLE  CLAMP,  same  as  above,  but  with  central  (zero)  point  indi¬ 

cated.  V  opening  to  clamp  to  19  millimeter  rod,  hole  for  10  millimeter  rods .  .78 

6-820  - ,  same  as  above,  but  V  opening  to  clamp  19  millimeter  rod,  hole  13  millimeters  .......  .85 


5-826  RIGHT  ANGLE  CLAMP  WITH  SLIDING  SPRING  CONTACT,  same  as  No.  5-816,  but  with  addi¬ 
tion  of  device  which  holds  clamp  firmly  to  the  bed-rod  yet  at  same  time  allowing  of  firm  sliding 
motion  along  the  rod.  This  clamp  is  advised  for  use  as  support  for  Photometer  Boxes  as  it  allows 
of  motion  along  rod  without  unlocking  the  set  screw  .  .  .  . . .  Each  1.70 


i8 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


No.  5-840 

Patent  Pending. 


6-840  SWIVEL-CLAMP  UNIVERSAL  HOLDER,  for  holding  in  any  position  flat  or  round  objects, 
thermometers,  burettes,  tubes,  screens,  telescopes,  telescope  scales,  and,  in  fact,  any  object  flat  or 
cylindrical  which  is  not  over  50  millimeters  in  diameter  nor  over  155  millimeters  wide  and  30  milli¬ 
meters  thick. 

This  device  consists  essentially,  of  two  parts, — a  holder  and  a  swivel-clamp,  the  holder  attached  to 
the  swivel-clamp  in  an  ingenious  manner  by  which  it  may  be  firmly  set  in  position  by  a  T  screw, 
and  yet  without  removing  from  the  rod,  capable  of  universal  motion  in  one  plane  by  simply  dimin¬ 
ishing  the  pressure  of  the  screw  against  the  rod.  This  swivel-clamp  will  be  found  a  prominent 
feature  in  the  use  of  this  holder. 

.  The  holder  is  designed  to  meet  the  requirements  of  a  general  lecture  table  clamp.  The  essential  part 
is  a  broad  plate.  At  the  edge  of  this  broad  plate  are  two  projections  against  which  the  object  to  be 
held  is  laid.  A  plunger  rod  carries  an  arm  which  is  adjustable  along  the  rod  and  it  in  turn  carries 
an  adjustable  contact  rod  tipped  with  cork.  In  use  the  object  is  placed  against  the  projections  at 
the  edge  of  the  broad  plate.  Knob  at  end  of  plunger  rod  is  pushed  in,  thus  acting  against  a  com¬ 
pression  spring.  The  arm  carrying  the  contact  rod  is  adjusted  on  the  plunger  rod  and  the  posi¬ 
tion  of  the  contact  rod  on  this  arm  is  adjusted  so  that  when  pressure  of  thumb  is  removed  from 
compression  spring  the  object  is  firmly  clamped  by  force  of  the  spring.  (See  Figure  1.)  The  pro¬ 
jection  to  the  rear  of  the  arm  is  a  straight  rod  to  be  used  with  arm  reversed  on  plunger  rod  when  a 
flat  object  is  to  be  clamped.  (See  Figures  2  and  3.) 

This  Universal  Holder  will  be  found  a  valuable  addition  to  any  laboratory.  Its  use  is  unlimited; 
positions  possible  are  multitudinous;  facility,  convenience,  and  rapidity  of  changes  are  unexcelled. 

As  it  will  hold  a  great  range  of  sizes  from  small  to  large,  adapting  itself  instantly  to  these  changes, 
and  support  objects  in  any  position  it  might  well  be  called  a  system  of  clamps  combined  in  one. 

It  is  handsomely  finished  in  bright  nickel-plate.  All  parts  are  carefully  fitted  and  substantial  in 
structure.  The  most  convenient  and  generally  useful  lecture  table  clamp  yet  designed.  Two 
should  be  provided  for  each  lecture  table . Each  $4.60 


I 


Fig.  2 


Fig.  3 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


19 


Nos.  6-850  and  6-866 


No.  6-875 


6-860  UNIVERSAL  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  various  planes  at  right  angles  to 

each  other.  Provided  with  swivel  for  locking.  Two  V  openings  to  clamp  19  millimeter  rods  .  .  .  $1.06 

&-856  - ,  same  as  above,  but  with  two  V  openings  for  clamping  13  millimeter  rods . 90 

5-876  UNIVERSAL  CLAMP,  for  large  objects  up  to  8  centimeters  in  diameter,  regular  or  irregular  in  shape. 

Position  adjustable  by  swivel  through  180  degrees.  Finished  in  japan  and  nickel  plate .  1.76 


No.  5-886  No.  6-889  No.  6-895 


6-885  BOTTLE  CLAMP,  for  clamping  a  bottle  by  its  neck  and  supporting  same  to  an  upright.  V  clamp 
for  13  millimeter  rod.  Will  clamp  firmly  any  diameter  from  25  millimeters  to  30  millimeters.  In 
use  see  No.  63-200  . $0.85 

5- 887  ADJUSTABLE  TUBE  CLAMP,  for  supporting  a  tube  in  an  upright  or  horizontal  position.  This  is 

a  two-part  casting,  one  part  designed  with  a  V  clamp  for  attaching  to  a  13  millimeter  rod,  the 
second  part  held  adjustably  to  the  first  by  two  thumb  screws,  thus  accommodating  a  tube  from 
134  inches  (32  millimeters)  to  1  %  inches  (45  millimeters)  in  diameter.  In  use  see  No.  63-200  .  .96 

6- 889  ADJUSTABLE  ARM  SUPPORT  WITH  CLAMP.  This  is  a  two-part  casting,  one  provided  with  a 

V  for  clamping  to  a  13  millimeter  rod,  the  other  with  countersunk  hole  at  the  end  of  a  slotted  arm. 

This  arm  is  adjustable  to  the  length  of  the  slot  and  may  be  clamped  in  any  position  by  means  of  a 
thumb  screw.  In  use  see  No.  63-200  . 85 

6-891  ROD  V  CLAMP,  for  use  with  any  V  clamp  in  securing  a  greater  latitude  of  adjustment.  V  opening 

to  take  10  or  13  millimeter  rod.  Rod  13  millimeters  diameter,  11  centimeters  long . 65 

6-895  METER  STICK  CLAMP,  V  opening  for  clamping  to  a  13  or  19  millimeter  rod,  face  plate  and 
adjustable  locking  device  for  holding  the  standard  meter  stick.  Surfaces  of  V  and  of  face  plate 
carefully  milled  parallel . . . 64 


20 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


5-900  FOUR  PENDULUM  CLAMP,  for  adjustably  supporting  four  pendulums.  This 
clamp,  similar  in  design  to  the  one  on  the  market  is  improved  so  that  it  may 
carry  four  pendulums,  thus  making  possible  a  direct  comparison  of  pendulum 
lengths  of  periods  as  1:  2:  3:  4.  The  clamp  itself  is  of  a  smooth,  uniform  casting, 
carrying  four  removable  clamps  designed  to  give  exact  points  of  suspension 
for  accurate  measurement  of  lengths.  This  clamp  consists  of  a  flat  brass  piece 
with  guide  pin  held  to  the  main  clamp  by  a  polished  and  lacquered  thumb 


screw .  . $1.75 

5-902  THREE  PENDULUM  CLAMP,  similar  to  above  but  usual  form  designed  to  hold 

three  pendulums .  .76 

For  Complete  Pendulum  Apparatus,  see  Section  25. 


No.  6-905 


5-905  BI-FILAR  PENDULUM  CLAMP  for  holding  four  pendulums  in  bi-filar  suspensions. 

This  clamp  obviates  the  inconveniences  of  the  ordinary  type  in  that  it  gives  a  direc¬ 
tive  force  to  the  swinging  pendulums.  It  is  especially  adapted  for  four  pendulums 
of  different  vibration  periods. 

It  consists  of  a  smooth  uniform  casting  in  which  are  placed  tapered  plugs,  two  for  each 
pendulum  ball.  These  tapered  plugs  are  carefully  fitted  to  their  respective  holes, 
and  the  lengths  of  the  suspending  cords  are  readily  adjusted  and  held  by  the 
friction  of  the  tapers  against  the  sides  of  the  holes  .  .  ., . $2.36 

For  Complete  Apparatus,  see  Section  26. 


No.  5-916 


5-915  HAND  BALANCE  SUPPORT  or  CLAMP  for  attaching  to  a  Tripod  Stand,  and 
supporting  adjustably  a  hand  balance.  This  clamp  is  designed  for  use  on  a  13 
millimeter  rod.  In  use,  a  stiff  tape,  a  shoestring  being  excellent,  is  threaded 
through  the  ring  of  the  hand  balance  and  then  the  ends  threaded  through  the 
holes  in  the  clamp,  then  wrapped  once  about  the  binding  screw. 

Height  of  the  balance  is  readily  adjusted, 'first  (coarse  adjustment),  by  position  of 
clamp  on  the  rod,  second  (fine  adjustment),  by  drawing  tape  through  the  holes  in 
the  clamp . $0.28 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


21 


No.  5-920 

5-920  TELESCOPE  CLAMP,  for  holding  any  round  or  square  object  from  7.5  to  16  centimeters  in  length, 
especially  designed  for  holding  Reading  Telescopes.  This  clamp  is  constructed  of  metal  through¬ 
out,  with  clamping  device  consisting  of  two  V’s  adjustable  along  the  clamping  rod  to  accommodate 
the  different  lengths  of  the  objects.  A  strap  adjustable  to  the  size  of  the  object  is  designed  to 
bind  it  without  danger  of  injury.  The  clamping  rod  is  tapped  by  20  on  two  faces  to  take  the 
10  millimeter  rod,  securing  positions  as  may  be  noted  in  the  illustration . $2.45 


MECHANICAL  ROTATOR 


Mounted  horizontally 

The  accompanying  illustrations  show  the  method  employed  in  setting 
up  a  Mechanical  Rotator,  using  the  attachments  listed  below  in  conjunction 
with  No.  5-350  Table  Clamp  and  No.  6-20e  Support  Rod. 

6-926  MECHANICAL  ROTATOR  ATTACHMENTS,  consisting  of  a  Drive 
Wheel  and  Clamp  and  a  Spindle  and  Clamp,  the  latter  provided 
on  one  end  with  groove  for  belt,  socket  and  setscrew;  on  the  other, 


with  a  special  headed  lock  nut. 

Drive  Wheel  and  Clamp,  Spindle  and  Clamp  and  Round  Belt  .  .  .  $6.75 

6-926  DRIVE  WHEEL  and  CLAMP,  including  Round  Belt .  3.50 

6-927  SPINDLE  and  CLAMP,  one  end  grooved  for  round  belt  and  pro¬ 
vided  with  socket  and  set  screw;  other  with  special  headed  lock 

nut . . .  3.25 

6-928  ROUND  LEATHER  BELT  with  patent  belt  fastener .  .65 


For  other  Mechanical  Rotator  see  No.  21-10. 


Mounted  vertically 


22 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  » 


No.  6-960 


MOUNTED  PULLEYS,  MIRRORS 
LENS  HOLDERS,  ETC. 


No.  6-952 


No.  6-960 


No.  6-970 


No.  6-976 


6-960  BALL-BEARING  PULLEY  MOUNTED  ON  ROD,  axis  at  right  angles  to  rod.  Nickel  plated,  BALL¬ 
BEARING,  STEEL  PULLEY,  60  millimeters  diameter,  mounted  in  stirrup  and  attached  to  nickel- 
plated  rod,  10  millimeters  diameter,  15  centimeters  long.  These  MOUNTED  PULLEYS  must  not 
be  confused  with  the  brass  pulleys  mounted  on  cone  bearings,  as  by  means  of  ball  race  we  secure 
a  frictionless  pulley,  running  true,  tested  to  uphold  50  pounds . 

6-962  BALL-BEARING  PULLEY  MOUNTED  ON  ROD,  axis  in  same  plane  as  rod:  i.  e.,  pulley  will  run 
at  right  angles  to  rod.  BALL-BEARING  PULLEY,  60  millimeters  diameter,  mounted  on  nickel- 
plated  rod,  10  millimeters  diameter,  15  centimeters  long,  pulley  tested  to  uphold  50  pounds  .  . 

6-960  ADJUSTABLE  60  M.  M.  PLANE  MIRROR  ON  ROD.  Mirror  50  millimeters  diameter,  adjustable 
in  stirrup  about  a  horizontal  axis,  adjustable  on  rod  about  a  vertical  axis.  Mounted  on  nickel- 
plated  rod,  10  millimeters  diameter,  15  centimeters  long . 

6-970  UNIVERSAL  LENS  HOLDER,  for  lenses  up  to  4  inches  in  diameter.  This  ingenious  holder  is  adjust¬ 
able  by  means  of  the  rods  and  set  screws  to  hold  and  clamp  firmly  in  or  off  center,  lenses  up  to 
4  inches  diameter.  Handsomely  oxidized  black  with  nickel-plated  rods . 

5-976  -  — ,  same  as  above,  for  holding  lenses  up  to  2  inches  in  diameter . 


$0.94 

.90 

1.96 


.88 


.78 


t 


BASES,  SUPPORT  RODS,  CLAMPS 

No.  6-990  LECTURE  LIST  “A” 

A  carefully  selected  list  of  bases,  rods,  clamps,  and  attachments,  covering  the  essentials  and 
designed  for  schools  not  in  position  to  procure  a  more  complete  outfit: 


Quan. 

Number 

Item 

Quan. 

Number 

Icem 

SUPPORT  BASES 

MISCELLANEOUS 

2 

6-260 

Eccentric  leveling  Bases 

1 

6-540 

Platform 

4 

6-646 

Hook  Collars  for  13  mm.  rod 

SUPPORT  RODS 

1 

6-950 

Pulley  on  rod 

1 

6-1 5b 

Support  Rod  13  mm. 

X  40  cm. 

2 

5-952 

Pulleys  on  rod 

1 

6-15c 

“  “  13  mm. 

X  60  cm. 

1 

6-976 

Universal  Lens  Holder 

1 

6-20b 

“  “  19  mm. 

X  40  cm. 

1 

5—40b 

“  “  19  mm. 

X  125  cm. 

T-BEAM  BASIC  CLAMPS 

2 

6-20e 

“  “  19  mm. 

X  100  cm. 

2 

6-1000 

Basic  Clamps  “A” 

2 

6-1160 

Basic  Clamps  “B” 

CLAMPS 

• 

1 

6-1006 

Basic  Rod  Swivel  Clamp 

2 

6-460 

Extension  Clamps 

1 

6-1026 

Single  Rod  Attachment 

2 

6-766 

Right  Angle  Clamps 

1 

6-1030 

Three  Rod  Attachment 

2 

6-770 

Right  Angle  Clamps 

1 

6-1036 

Swivel  Post  Attachment 

1 

6-860 

Swivel  Clamp 

2 

5-1060 

Knife  Edge  Attachments 

1 

5-895 

Meter  Stick  Clamp 

1 

6-1070 

Balance  Cradle 

1 

6-900 

Pendulum  Clamp 

1 

5-1080 

Pulley  Clamp 

6-990  LECTURE  LIST  “A”  complete,  as  listed  above  .  .  .  . 

( See  next  page  ) 


Set  $36.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


23 


BASES,  SUPPORT  RODS,  CLAMPS 

No.  5-995  LECTURE  LIST  “B” 


The  following  list  has  been  made  up  by  teachers  of  long  experience  and  is  considered  and  ad¬ 
vised  by  them  as  an  equipment  ample  for  lecture  table  demonstrations.  The  selection  has  been 
made  with  the  intention  of  covering  every  need  for  the  lecture  table,  with  suitable  bases,  support 
rods,  clamps,  and  attachments  which  will  be  needed  in  assembling  and  adjusting  the  apparatus 
used  in  the  most  complete  lecture  table  demonstration  courses.  Suggestions  for  enriching  this 
list  either  by  new  designs  or  by  additions  of  old  will  be  greatly  appreciated. 


Quan.  Number  Item 

Quan. 

Number 

Item 

SUPPORT  BASES 

CLAMPS 

1 

6-101 

Tripod  Base,  6  cm.  for  10  mm.  rod 

1 

5-891 

Rod  V  Clamp 

2 

6-106 

“  8  cm.  for  10  mm.  rod 

1 

5-896 

Meter  Stick  Clamp 

1 

6-114 

“  12  cm.  for  10  mm.  rod 

1 

5-900 

Pendulum  Clamp 

2 

6-116 

“  12  cm.  for  10  mm.  rod 

1 

6-906 

Bi-filar  Pendulum  Clamp 

1 

6-140 

“  “  18  cm.  for  19  mm.  rod 

1 

5-170 

“  26  cm.  for  30  mm.  rod 

MISCELLANEOUS 

4 

2 

6-260 

6-262 

Eccentric  Leveling  Bases,  11J^-18J4  inches 
“  “  “  18^-32  inches 

1 

1 

6-610 

6-516 

Adj.  Lab.  Stand,  40-70  cm. 

“  “  “  70-130  cm. 

SUPPORT  RODS 

1 

1 

6-626 

6-627 

Platform,  rod  10  mm.,  7  X  8.5  cm. 

“  rod  19  mm.,  7  X  8.5  cm. 

2 

6-10b 

Support  Rods,  10  mm.  X  15  cm. 

1 

6-630 

rod  10  mm.,  8.5  X  11.5  cm. 

2 

5-10c 

“  “  10  mm.  X  20  cm. 

1 

6-636 

rod  13  mm.,  8.5  X  11-5  cm. 

2 

5-10e 

“  “  10  mm.  X  40  cm. 

1 

5-640 

rod  13  mm.,  11.5  X  15.5  cm. 

2 

6-16b 

“  “  13  mm.  X  40  cm. 

1 

6-646 

rod  19  mm.,  14.5  X  21.5  cm. 

2 

6-16c 

“  “  13  mm.  X  60  cm. 

1 

6-260 

Plate  Base 

2 

5-16e 

“  13  mm.  X  100  cm. 

1 

5-480 

Stand  Top,  20  cm.  for  13  mm.  rod 

2 

5-20b 

“  “  19  mm.  X  40  cm. 

1 

6-486 

“  20  cm.  for  19  mm.  rod 

2 

6-20c 

“  19  mm.  X  60  cm. 

1 

6-490 

“  “  30  cm.  for  19  mm.  rod 

2 

5-20e 

“  “  19  mm.  X  100  cm. 

1  pr. 

6-376 

End  Supports 

1 

6-20f 

“  “  19  mm.  X  120  cm. 

1  pr. 

6-386 

Secondary  Supports 

1 

6-3Qd 

“  “  30  mm.  X  120  cm. 

1  pr. 

6-690 

Knife  Edge  Brackets 

1 

6— 40a 

“  “  19  mm.  X  100  cm. 

1  set  6-610 

Leveling  Screws 

1 

6-40c 

“  “  19  mm.  X  185  cm. 

1 

6-636 

Collar  for  30  mm.  rod 

1 

6-50d 

“  “  19  mm.  X  100  cm. 

2 

6-636 

“  for  19  mm.  rod 

1 

6-60e 

“  “  19  mm.  X  120  cm. 

1 

6-637 

“  for  13  mm.  rod 

1 

6-400 

Stand  Tube,  20  cm.  for  13  mm.  rod 

1 

6-638 

“  for  10  mm.  rod 

1 

6-406 

“  30  cm.  for  13  mm.  rod 

6 

6-646 

Hook  Collars  for  10  mm.  rod 

1 

6-410 

“  30  cm.  for  19  mm.  rod 

10 

6-646 

“  “  for  13  mm.  rod 

1 

6-416 

“  40  cm.  for  19  mm.  rod 

4 

6-950 

Pulleys  on  rod 

4 

6-952 

“  on  rod 

CLAMPS 

1 

6-960 

Mirror  on  rod 

2 

2 

6-360 

6-460 

Table  Clamps 

Extension  Clamps 

1 

1 

6-970 

6-975 

Universal  Lens  Holder,  lenses  up  to  4- 
“  “  “  “  up  to  2- 

2 

2 

6-726 

6-736 

Right  Angle  Clamps 

“  “  “  V,  19  mm.  hole  13  mm. 

T-BEAM  BASIC  CLAMPS 

1 

6-746 

“  “  “  V,  30  mm.  hole  19  mm. 

“  “  “  2  V’s,  13  mm. 

4 

6-1000 

Basic  Clamps  “A” 

2 

6-760 

2 

6-1160 

Basic  Clamps  “B” 

2 

6-766 

“  “  “  2  V’s,  19  mm. 

2 

6-1005 

Basic  Rod  Swivel  Clamps 

4 

6-770 

“  “  “  2  V’s,  19  mm 

1 

6-1026 

Single  Rod  Attachment 

1 

6-786 

“  “  “  V,  19  mm.,  tapped 

2 

6-1030 

Three  Rod  Attachments 

X  X  20 

1 

6-1036 

Swivel  Post  Attachment 

1 

6-790 

“  “  “  V,  19  mm.,  tapped 

2 

6-1045 

Secondary  Basic  Attachments 

X  X  16 

1 

6-1060 

Upright  Secondary  Attachment 

5 

6-810 

“  “  “  for  optical  bench 

1 

6-1066 

Meter  Stick  Attachment 

1 

6-826 

“  “  “  for  photometer 

2 

6-1060 

Knife  Edge  Attachments 

1 

6-840 

Universal  Clamp 

*4 

6-1066 

Stone’s  Tension  Clamp  Attachments 

1 

6-860 

Swivel  Clamp  for  19  mm.  rods 

4 

6-1070 

Balance  Cradle  Attachments 

1 

6-866 

“  “  for  13  mm.  rods 

1 

6-1076 

Micrometer  Screw  Attachment 

1 

6-876 

Universal  Clamp 

1 

6-1080 

Universal  Pulley  Attachment 

1 

6-887 

Adjustable  Tube  Clamp 

1 

6-1085 

Chladni’s  Plate  Attachment 

1 

6-889 

Adjustable  Arm 

1 

6-1185 

Bench  Anvil-Vise  Attachment 

6-996  LECTURE  LIST  “B”  complete,  as  listed  above 


Set  $173.00 


24 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


HARCOURT  UNIVERSAL  T-BEAM 

CLAMPS 

The  Harcourt  Universal  T-Beam  Clamps  have  been  so  designed  that  they  accomplish  three 
very  important  results: 

FIRST:  They  supply  to  the  instructor  a  series  of  clamps 

which,  with  appropriate  rods,  will  enable  him  to 
set  up  his  apparatus  in  a  minimum  amount  of  time. 

SECOND:  They  hold  the  apparatus,  when  so  set  up,  cor¬ 
rectly  and  rigidly. 

THIRD:  They  do  this  at  a  reasonable  cost. 


The  line  which  is  listed  in  the  following  pages,  with  its  lathe-rest  interlocking  attachments 
and  interchangeable  features,  gives  latitude  of  operation  never  before  obtained  with  laboratory 
accessories. 

The  Harcourt  Universal  T-Beam  Clamps  are  divided  into  two  groups,  Series  “A”  and 
Series  “B.”  In  the  first  series  are  two  basic  clamps:  the  Harcourt  Universal  T-Beam  Basic  Clamp 
“A”  and  the  Basic  Rod  Clamp.  To  these  basic  clamps  may  be  clamped  the  various  Lathe-rest 
Interlocking  Attachments.  In  Series  “B”  only  one  basic  clamp  is  required,  as  this  series  is  de¬ 
signed  only  for  heavier  work,  the  nature  of  which  would  prohibit  its  use  on  a  rod.  The  Lathe- 
rest  Interlocking  Attachments,  therefore,  in  this  series  are  few  compared  with  those  listed  in 
Series  “A.” 

Illustrations  covering  the  vast  utility  of  these  series  are  practically  impossible.  We  secure 
a  greater  range  of  usefulness  and  stability  with  our  series  than  heretofore  obtained  by  any  other 
system  of  laboratory  hardware.  In  our  experiments,  we  have  been  able  to  cover  practically 
the  entire  field  of  the  “Interchangeable  Laboratory  Supports”  by  the  few  attachments  which 
are  herewith  listed,  widening  the  field  and  adding  to  the  interchangeable  features.  If  any  po¬ 
sition  or  “set-up”  is  desired  that  is  neither  illustrated  nor  can  be  procured  with  our  line,  we  most 
urgently  request  the  co-operation  of  the  teachers  in  making  known  their  particular  needs. 

On  the  following  pages  we  have  listed  these  two  series  of  Basic  Clamps  and  Interlocking 
Lathe-rest  Attachments.  It  has  seemed  impracticable,  however,  in  this  catalogue  to  show  by 
illustrations  and  descriptions  the  many  ways  by  which  the  few  designs  can  be  utilized  to  ad¬ 
vantage  in  the  lecture  desk  demonstrations  that  previous  to  the  introduction  of  this  line  required 
the  many  designs  heretofore  offered. 

In  a  special  circular,  now  in  press,  we  have  endeavored  to  picture  a  few  of  the  many  exper¬ 
iments  where  intelligent  use  of  Basic  Clamps  and  Interlocking  Attachments  greatly  simplifies 
lecture  and  laboratory  conduct.  Send  for  this  circular. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


25 


SERIES  “A” 

(Letters  used  in  the  following  descriptions  refer  to  corresponding  letters  in  illustration  above.) 

5-1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A”  for  clamping  to  a 
table  or  any  surface  not  over  6  centimeters  thick,  as  the  fundamental  support 
for  attaching  any  of  our  Universal  Lathe-rest  Interlocking  Attachments  listed 
in  this  series,  (“a”  in  illustration.) .  . $0.94 

5-1005  HARCOURT  UNIVERSAL  T-BEAM  BASIC  ROD  SWIVEL  CLAMP  for  clamp¬ 
ing  to  any  13  or  19  millimeter  rod  for  attaching  any  of  our  Universal  Lathe- 
rest  Interlocking  Attachments  listed  in  this  series,  (“b”  in  illustration.)  As 
may  be  noted  from  the  illustration  of  this  clamp,  it  is  in  design  similar  to  the 
Basic  Clamp  “A.”  It  has  a  further  important  feature,  however,  impossible  of 
adequate  illustration.  This  feature  allows  of  clamping  the  double  bevel  slide 
in  any  position  without  movement  of  the  clamp  along  the  rod.  The  universal 
movement  is  secured  by  means  of  an  ingenious  swiveled  V-clamp  device  read¬ 
ily  operated  by  the  nickel-plated  T-Screw . 1.65 


26 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


• t 


UNIVERSAL  LATHE-REST  INTERLOCKING 

ATTACHMENT 

SERIES  “A” 


6-1025 

6-1030 

6-1035 

5-1040 

5-1046 

5-1050 

5- 1055 

6- 1060 

5- 1065 

6- 1070 

5- 1076 

6- 1080 
6-1085 
6-1090 


5-1160 


5- 1176 

6- 1180 


5-1185 


5-1186 


SINGLE-ROD  ATTACHMENT  for  holding  a  10  millimeter  rod  either  perpendicular  or  parallel  to 
face  of  clamp.  The  rod  is  clamped  rigidly  in  place  by  means  of  a  nickel-plated  T  screw.  (“c” 

in  illustration.)  In  use,  see  No.  23-10 . . .  $0.68 

THREE-ROD  ATTACHMENT,  tapped  %  X  20,  %  X  16,  and  M  X  12,  to  hold  either  a  10,  13  or  19 

millimeter  rod.  (“d”  in  illustration.) . • .  .66 

SWIVEL-POST  ATTACHMENT  for  clamping  a  13  millimeter  rod  which  may  be  swiveled  through 
an  arc  of  180  degrees  and  fixed  in  any  position  by  a  wing  nut.  (“e”  in  illustration.)  In  use,  see 

Adjustable  Inclined  Plane  Support,  Section  25 .  .84 

THREADED  SWIVEL-POST  ATTACHMENT,  similar  to  above,  but  provided  with  a  boss  threaded 
to  receive  any  rod  tapped  %  X  16.  (“f”  in  illustration.)  In  use,  see  Hand  Air  Pump,  Section  42  .74 

SECONDARY  BASIC  ATTACHMENT  for  use  in  conjunction  with  Basic  Clamp  “A”  to  secure  a 
lathe-rest  support  at  right  angles  to  that  of  the  basic  clamp,  (“g”  in  illustration.)  .......  .66 

UPRIGHT  SECONDARY  BASIC  ATTACHMENT  for  use  in  conjunction  with  Basic  Clamp  “A,” 

lathe-rest  slide  perpendicular  to  clamp,  (“h”  in  illustration.) . .  .68- 

METER  STICK  ATTACHMENT  for  clamping  a  meter  stick  in  an  upright  position,  (“i”  in  illustra¬ 
tion.)  .  .74 

KNIFE-EDGE  ATTACHMENT,  (“j”  in  illustration.)  In  use  see  Knife-Edge  Clamp,  Section  5; 

also  Bending  Beam  Apparatus,  Section  23 . '  .66- 

STONE’S  TENSION  CLAMP  ATTACHMENT,  (“k”  in  illustration.)  In  use,  see  Parallelogram 

of  Force  Apparatus,  Section  24 .  .48 

BALANCE  CRADLE  ATTACHMENT,  designed  for  the  standard  250,  500  or  2000  gram  Spring  Bal¬ 
ances.  (“1”  in  illustration.)  In  use,  see  Parallelogram  of  Force  Apparatus,  Section  24 .  .66 

MICROMETER  SCREW  ATTACHMENT,  swiveled  split-post  tension,  (“m”  in  illustration.)  For 
complete  description,  see  Micrometer  Screw,  Section  12.  In  use,  see  Flexure  of  Beams  Apparatus, 

Section  23 . : .  3.26 

UNIVERSAL  PULLEY  ATTACHMENT,  (“n”  in  illustration.)  For  complete  description  see 

Universal  Pulley,  Section  27 . ‘ .  1.76 

CHLADNI’S  PLATE  ATTACHMENT,  (“o”  in  illustration.)  In  use,  see  Chladni’s  Figures  Appara¬ 
tus,  Section  54 . * . .  .60 

ROD  V  CLAMP  ATTACHMENT  (“t”  in  illustration.)  This  clamp  will  be  required  if  it  is  desired  to 
clamp  one  rod  to  another,  especially  in  obtaining  a  cross-bar  support .  .68 


SERIES  “B  ” 


(Letters  used  in  following  descriptions  refer  to  corresponding 


letters  in  illustration  on  preceding  page.) 


HARCOURT  UNIVERSAL  T-BEAM  BASIC 
CLAMP  “B”  for  clamping  to  a  table  or  any 
surface  not  over  8J^  centimeters  thick  as  the 
fundamental  support  for  attaching  any  of  our 
Universal  Lathe-rest  Interlocking  Attach¬ 
ments  listed  in  this  series,  (“p”  in  illus¬ 
tration.)  The  top  plate  is  drilled  and 
threaded  for  taking  any  of  our  19  mm. 
threaded  support  rods.  It  will  be  found 
particularly  useful  for  holding  the  up¬ 


rights  on  our  Physics  Table  No.  1-120  .  .  $1.65 

BALL-BEARING  TORSION  OF  BEAMS 
ATTACHMENT,  (“s”  in  illustration.)  In 
use  and  for  description,  see  Torsion  Appa¬ 
ratus,  Section  23 .  3.90 

FIXED  HEAD  TORSION  OF  BEAMS  AT¬ 


TACHMENT.  (“r”  in  illustration.)  In 
use  and  for  description,  see  Torsion  Appa¬ 
ratus,  Section  23.  May  be  used  in  four 

positions .  1.35 

BENCH  ANVIL-VISE  ATTACHMENT,  in¬ 
terlocking  with  Basic  Clamp  “B”  to  secure 
a  rigid,  substantial  bench  anvil  vise.  Spread 
5J4  inches,  jaws  2%  inches.  Provided  with 


hardened  steel  cutting-off  tool .  7.45 

BENCH  ANVIL-VISE,  consisting  of  No. 

5-1160  Basic  Clamp  and  above  attach¬ 
ment,  complete .  9.10 


No.  5-1186  Patent  Pending. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


27 


DIRECTION  SHEETS 

FOR  LOOSE-LEAF  SYSTEM  OF  INSTRUCTION 

By  GEORGE  M.  TURNER  and  C.  BROOKS  HERSEY 


Masten  Park  High  School,  Buffalo,  N.  Y. 


Perhaps  the  most  distressing  problem  confronting  the  science  teacher  is  that  of  the  choice 
of  a  suitable  laboratory  guide  for  his  classes.  Requirements  differ  in  different  localities.  These 
requirements  are  governed  by  many  factors,  principal  among  which  may  be  cited  the  following, 
—  some  localities  are  manufacturing  centers,  some  agricultural,  in  short,  an  industrial  factor; 
some  schools  are  not  equipped  to-  teach  from  any  one  laboratory  guide,  a  condition  arising  per¬ 
haps  from  frequent  changes  in  the  instruction  force,  each  of  whom  had  individual  methods. 
Last,  but  not  least,  is  the  all-important  factor  of  non-uniformity  of  College  Entrance  Require¬ 
ments  throughout  the  country. 

Many  instructors  have  solved  the  problem  of  meeting  the  individual  school  demands  by 
formulating  manual  directions  to  meet  their  own  particular  conditions,  but  the  problem  had 
never  been  satisfactorily  faced  until  Messrs.  Turner  and  Hersey  edited  and  authorized  for  pub¬ 
lication  the  LOOSE-LEAF  NATIONAL  PHYSICS  NOTE-BOOK  DIRECTION  SHEETS.  In 
this  publication,  in  which  we  have  SOLE  SELLING  RIGHTS,  a  teacher  is  given  a  latitude 
for  choice,  and  the  extensive  sale  of  these  sheets  has  demonstrated  their  success  in  meeting  the 
particular  individual  demand  of  the  many  who  use  them  in  preference  to  bound  manuals. 

The  number  of  experiments  covered  up  to  the  issuance  of  this  catalogue  is  132.  In  this  list 
will  be  found,  not  only  a  latitude  for  choice  of  experiments  but  also  for  choice  in  method,  thus- 
meeting  the  demand  for  Manual  Directions  to  conform  to  individual  equipments.  As  this  num¬ 
ber  is  constantly  increasing  to  keep  pace  with  the  advances  made  in  science  teaching,  the  NA¬ 
TIONAL  PHYSICS  NOTE-BOOK  WILL  NEVER  BECOME  OBSOLETE. 

Results  of  experience  developed  the  following  features: 

Saving  in  the  Teacher’s  Time. 

Saving  in  the  Pupil’s  Time. 

Intense  Interest  Aroused  in  Pupils. 

Clearness  in  the  Ideas  Developed. 

Perfect  Adaptability  to  Meet  each  Local  Requirement. 

Flexibility, — Meeting  Teachers’  Individual  Desires. 

Space  does  not  permit  of  a  complete  INDEX  of  the  NATIONAL  PHYSICS  NOTE-BOOK, 
but  upon  request  we  will  mail  gratis  a  COMPLETE  INDEX  with  typical  direction  sheets.  We 
have  in  our  files  many  courses  which  are  used  with,  complete  satisfaction  by  thousands  of  schools, 
and  have  prepared  for  distribution  PRINTED  INDICES  covering  requirements  of  many  States, 
each  course  having  been  tested  and  found  highly  satisfactory.  These  INDICES,  with  typical 
direction  sheets,  will  be  mailed  upon  request. 

National  Physics  Experiment  Sheets . Each  net  $0.01 

Note. — Any  selection  or  number  of  experiments  in  the  series  may  be  ordered  at  rate  given. 

Certification  Sheets . .  .  Each  net  .01 

Harcourt  Binders,  cloth  backs,  with  binding  cord,  for  holding  National 

Physics  Experiment  Sheets . Each  net  .18 


28 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


HARCOURT  PORTRAITS 

OF 

SCIENTISTS 


The  HARCOURT  PORTRAITS  OF  SCIENTISTS  are  admirably  adapted  to  mural  decora¬ 
tions.  They  are  faithful  likenesses,  many  being  reproductions  in  platinum  prints  from  paint¬ 
ings  by  renowned  artists.  They  are  made  on  heavy  paper,  8  X  10  inches.  When  framed,  they 
should  measure  16  X  20  inches,  thus  affording  a  size  that  will  be  highly  decorative  and  ample 
for  class  or  lecture-room  use.  < 

Additions  to  our  series  are  made  from  time  to  time,  but  the  present  Harcourt  Series  numbers 
26,  as  follows: 


CHEMISTS 

Priestley 

Faraday 

Wohler 

Lavoisier 

Bunsen 

Moissan 

Dalton 

Ostwald 

Remsen 

Davy 

Liebig 

Pasteur 

Mendelejeff 

Boyle 

PHYSICISTS 

Newton 

Tyndall 

Rowland 

Faraday 

Helmholtz 

Galileo 

Henry 

Kelvin 

Boyle 

BIOLOGISTS 

Pasteur 

Linnaeus 

Cuvier 

Huxley 

Darwin 

Spencer 

Single  Portraits,  postpaid, 
Choice  any  6, 

Choice  any  12, 


$  1.00 
5.40 
10.00 


THE  MILLER  COLLECTION  OF 

LANTERN  SLIDES  IN  PHYSICS 


From  the  negatives  of  Fred  R.  Miller,  Instructor  of  Physics 
in  the  Boston  English  High  School. 

The  slides  in  this  collection  cover  the  various  branches  of  Physics  and  offer  to  the  prospec¬ 
tive  buyer  considerable  latitude  for  choice.  The  subjects  were  selected  to  conform  to  the  peda¬ 
gogic  demands.  Thus  there  will  be  found  not  only  the  modern  types  of  machines,  but  slides 
showing  historical  development  as  well.  The  sectional  and  diagrammatical  slides  will  be  found 
of  special  value. 

This  collection  is  continually  increasing,  but  at  the  time  of  issuance  of  this  catalogue,  num¬ 
bered  324,  —  Mechanics  75;  Heat  99;  Light  40;  Sound  10;  Electricity  100. 


A  descriptive  circular  will  be  sent  upon  request. 

Single  slides . Each  $  0.40 

Any  50  will  be  furnished  in  a  regular  Lantern  Slide  Box  for . 20.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


29 


10-10 


10-20 


ILLUSTRATIVE  DEMONSTRATION 

APPARATUS 


Used  by  express  permission  of  Copyright  owner 


No.  10-10 

LARGE  SIZE  METRIC  CHART,  presenting  graphically  a  comparative  grouping  of  the  Metric  and 
English  units  of  weights  and  measures. 

The  chart  is  50  inches  wide  and  46  inches  high,  and  the  illustrations,  beautifully  lithographed  in  colors, 
are  grouped  in  the  best  manner  for  direct  comparisons  of  the  two  systems.  The  type  is  large  and 
distinct  and  the  coloring  of  the  whole  chart  is  such  that  it  will  be  found  not  only  a  valuable,  but 
an  ornamental  accessory  to  any  laboratory. 

Mounted  on  cloth  back  and  provided  with  common  rollers  with  hooks  for  hanging . 


No.  10-20 

POLISHED  DISSECTED  LITER  BLOCK,  graduated,  dissected,  and  weighted  for  the  ocular  as  well 
as  quantitative  comparisons  in  the  Metric  System  of  length,  area,  volume,  capacity,  and  weight. 

This  block  is  graduated, — one  edge  to  millimeters,  each  face  into  square  centimeters;  dissectible  to 
1-10,  1-100,  and  1-1000  of  its  volume;  weighted  so  that  each  section  has  a  mass  equal  to  an  equivalent 
volume  of  water. 

Made  of  selected  hardwood,  oil  and  wax  finish,  all  graduations  showing  white . 


$2.50 


$3.00 


30 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  * 


B555I!5Hil 

liaRBQIHRN 


5 


li 

8M{ 


No.  10-25 


10-25  GRADUATED  SOLID  LITER  BLOCK,  for  illustrative  comparisons  of  units  of  length  and  volume  in 
the  Metric  System.  ‘ 

This  block  is  graduated  as  No.  10-20  but  neither  loaded  nor  dissectible. 

Made  of  selected  hardwood,  oil  and  wax  finish,  all  graduations  showing  white . $1.35 

10-30  UNGRADUATED  CUBIC  DECIMETER  LITER  BLOCK  for  illustration  of  size  of  one  cubic  deci¬ 
meter  (1000  cubic  centimeters). 

This  block,  not  being  graduated,  dissectible,  or  weighted,  does  not  have  the  same  pedagogic  value 
as  the  preceding,  yet  will  be  found  effective  in  the  review  of  facts  deduced  by  their  use. 

Made  of  hardwood  with  oil  and  wax  finish  .  .  .* .  .65 

Note. — Under  No.  10-50  will  be  found  listed  a  block  accurately  one  foot  on  an  edge.  It  will  be  found  a  valuable  addition  if  ocular 
comparison  of  size  of  cubic  liter  and  cubic  foot  is  desired. 


No.  10-35 


■■■■liiiiinH 
■  ■  ■  h  n  tin  uni  inn  iiiiiiiin 
>■■■■111111111111111111111 
■■■  ■  mu  uui  mii  linn  mu  mi 
■iwmiiiiiniiiii 
■■■■nmnni 
■  m  urn  urn  im  iim  miii  iiu 
■  his  mu  uit  iint  uui  mi 
jig  BHIli  Hill  1111  111  11  IIU! 
HpuUHUIIl 


No.  10-45 


10-35  BURNISHED  COPPER  LITER  CASE,  illustrating  quantitatively  metric  equivalents  in  measures  of 
capacity,  volume,  and  weight. 

This  case  is  constructed  so  that  each  edge  measures  10  centimeters  (one  decimeter),  having, 
therefore,  a  capacity  of  one  cubic  decimeter.  It  is  especially  adapted  to  the  study  of  Archimedes’ 
Principle  and,  applying  this  principle,  to  determining  the  specific  gravity  and  volume  of  any  irregular 
solid.  This  case  is  provided  with  glass  face  for  inspection  of  contents  of  case,  an  accurate  metal  scale 
for  measuring  contents,  and  a  stop-cock  for  inlet  or  outlet  of  water.  By  using  a  balance  it  may  be 
determined  that  for  every  millimeter  rise  or  fall  of  water  as  indicated  by  the  scale  the  net  weight 
varies  by  10  grams,  thus  demonstrating  that  one  gram  of  water  occupies  one  cubic  centimeter  space. 


Made  of  burnished  copper  with  water-tight  glass  face,  accurate  metal  scale  and  brass  inlet  cock  .  .  .  $3.00 

10-40  CUBIC  DECIMETER  LITER  CASE  with  capacity  for  holding  exactly  one  liter  of  water.  Accurately 

made  of  non-corrosive  metal,  measuring  one  decimeter  on  edge  internal  measurement .  1.10 

10-45  GRADUATED  CUBIC  DECIMETER  LITER  CASE,  same  as  No.  10-40  but  with  one  face  graduated 

into  square  centimeters .  1.60 

10-50  SOLID  CUBIC  FOOT  BLOCK,  furnishing  for  demonstrative  work  a  striking  illustration  of  the  size 
and  weight  of  a  cubic  foot  of  wood.  Used  also  to  advantage  in  density  demonstrations. 

Built  up  in  sections  to  prevent  warping  and  cracking,  weight  neatly  printed  in  large  type  on  one  face  7.65 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


3i 


No.  10-60 


10-60  COMPARATIVE  DENSITY  WOODEN  CUBES,  admirably  adapted  for  work  in  density,  offering 
also  objects  for  simple  measurements. 

A  set  of  eight  cubes,  each  accurately  4  centimeters  on  an  edge  and  each  of  different  woods  as  follows: 
mahogany,  satinwood,  poplar,  oak,  boxwood,  walnut,  ebony,  and  lignum-vitae.  Per  set,  in  card¬ 
board  case .  . .  $3.30 


No.  10-70 


10-66  CARDBOARD  STRIP  after  Turner  and  Hersey  (Exp.  M011)  for  study  of  principle  of  a  vernier 

caliper . .  $0.10 

10-70  LECTURE  ROOM  VERNIER  MODEL  for  demonstration  and  study  of  simple  vernier.  Model  has 
total  length  of  50  centimeters  and  is  divided  into  25  spaces  of  2  centimeters  each.  Divisions  and 
figures  are  clearly  defined  and  large  and  may  be  seen  across  the  ordinary  lecture  room. 

Made  of  wood  with  sandpaper  and  oil  finish .  1.60 

10-76  LECTURE  ROOM  VERNIER  CALIPER  MODEL  for  demonstrative  and  quantitative  work. 

This  Caliper  Model  is  30  centimeters  long  with  graduations  to  centimeters.  It  is  sufficiently  accurate 
for  most  simple  measurements,  for  the  vernier  will  give  readings  to  1  millimeter. 

Made  of  clear  grain  boxwood  neatly  finished,  metal  slides  nickel  plated .  2.95 

10-80  LECTURE  ROOM  VERNIER  ARC  MODEL,  demonstrating  principle  of  vernier  arc  in  angle  meas¬ 
urements. 

This  model  is  substantially  made  of  hardwood  with  arc  of  25  centimeters  radius,  vernier  slides  smooth¬ 
ly  and  graduations  are  clearly  and  accurately  made .  9.00 


No.  10-85 

10-86  SQUARE  COMPARATIVE  METER  STICK  for  teaching  the  general  principles  of  linear  measure  in  the 
Metric  System.  This  stick  is  a  full  meter  in  length  and  has  a  cross  section  measurement  of  2  cen¬ 
timeters.  First  side  is  graduated  into  centimeters  and  millimeters;  second,  into  centimeters 
only;  third,  into  decimeters  only;  fourth,  ungraduated.  The  second  and  third  sides  have  further 

feature  of  having  spaces  painted  alternate  black  and  white . . $1.50 

10-87  METER  STICK  (School  Meter),  of  maple,  2  cm.  square.  One  surface  plain  showing  simple  meter; 

second  face  graduated  to  tenths  or  decimeters;  third,  to  hundredths  or  centimeters;  fourth,  to 
thousandths  or  millimeters  with  divisions  showing  also  decimeters  and  centimeters.  Not  painted 
as  No.  10-85 . 68 


32 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  10-100 


10-100  BURNISHED  COPPER  LIQUID  MEASURES  for  quantitative  measures  of  capacity  and  for  illus¬ 
trative  teaching  of  units  of  capacity  in  the  metric  system. 

Consists  of  seven  measures,  —  one  litdr,  and  fractional  parts  of  liter  as  follows:  34  liter,  2  deciliters, 

1  deciliter,  34  deciliter,  2  centiliters,  and  1  ceiltiliter. 

Made  of  burnished  copper . $4.90' 

10-105  - ,  consisting  of  liter,  deciliter,  and  centiliter  measure?. 

Made  of  burnished  copper,  same  accuracy  as  No.  10-100.  Set  of  three  measures .  2.25 

10-110  LIQUID  MEASURES,  same  as  No.  10-100,  but  made  of  tin  and  with  the  addition  of  a  2-liter 

measure.  Set  of  eight  measures . . .  2.40 

10-115  BURNISHED  COPPER  LITER  MEASURE,  an  accurate  burnished  copper  liter  measure  ....  1.00 

10-120  BURNISHED  COPPER  QUART  MEASURE,  an  accurate  burnished  copper  quart  measure.  Useful 

in  conjunction  with  any  of  the  above  measures  in  comparing  units  in  Metric  and  English  systems  1.00 
10-126  WOOD  DRY  MEASURES,  34  bushel  to  1  quart,  5  pieces .  1.45 


MEASURES  OF  LENGTH 


No.  11-10 

11-10  METER  STICK  of  maple  wood.  Divided  one  side  into  fractional  parts  of  foot  and  inch  to  34  inch; 


other  side  into  fractional  parts  of  meter  and  centimeter  to  millimeters . $0.28' 

11-10A  METER  STICK  with  SET  SCREW  and  SLOT  after  Turner  and  Hersey  (Exp.  M151) . 38 

11-11  - -,  same  as  No.  11-10,  but  with  ends  tipped  with  brass .  .36 

11-16  HALF-METER  STICK,  same  quality  as  No.  11-11.  Tipped  with  brass .  .24 

11-20  DOUBLE-METER  STICK,  same  quality  as  No.  11-11.  Tipped  with  brass .  1.36 

11-40  TEN  CENTIMETER  METRIC  RULE  of  maple.  This  is  a  convenient  10  centimeter  length  cut  from 

a  meter  stick  and  will  be  found  of  great  utility  in  many  experiments . 07 


11-60  DOUBLE  BEVEL  BOXWOOD  RULE,  Metric  and  English  Scales,  with  34  inch  blank  ends.  On 
Metric  bevel  30.5  centimeters  are  divided  to  millimeters;  on  English,  12  inches  to  sixteenths.  Rule 


is  1234  inches  long,  J-g  inch  wide,  and  %  inch  thick.  Excellent  quality . Each  $0.12 

Per  doz.  1.40 

11-66  DOUBLE  BEVEL  MAPLE  RULE,  Metric  and  English  Scales  as  in  No.  11-60 . Each  .04 

Per  doz.  .40 


No.  11-60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


33 


J^r  ~ 


No.  11-65 

11-65  TRIANGULAR  BOXWOOD  RULE  AND  SCALE,  indispensable  for  rapid  draw¬ 
ing  to  scale  or  in  calculating  actual  dimensions  from  scale  drawings. 

This  Rule  and  Scale  has  the  merit  of  having  six  different  surfaces  for  graduation, 
and  there  are  offered  ten  different  scales  to  the  foot:  %2,  M,  Y%,  iHs.  Y, 

1,  \]/2,  and  3  inches  to  the  foot.  One  edge  graduated  to  sixteenths  of  an  inch. 

Made  of  boxwood,  hand  polished,  12J^  inches  long  with  Yi  inch  blank  ends  .  .  $0.56  No.  11-70 

11-70  VERTICALLY  MOUNTED  RULE.  Used  frequently  with  indicating  lever  in  bending  experiments  .  $0.16 

11-80  STRAIGHT-EDGE  RULE,  especially  designed  for  the  drawing  of  diagrams;  useful  in  light  experiments 
and  many  other  experiments,  chiefly  in  Mechanics. 

Made  of  light,  clear-grain  selected  stock . Per  Pair  .16 


No.  11-100 

11-100  STANDARD  STEEL  RULES,  Metric  and  English  Scales  subdivided  with  greatest  care  and  accuracy. 

The  5  and  10  centimeter  rules  listed  are  divided  as  follows:  first  corner  graduated  to  %  millimeter;  sec¬ 
ond,  to  1  millimeter;  third,  to  %4  inch;  fourth,  to  %oo  inch.  The  remaining  listed  rules:  first  corner,  to  Y 
millimeter;  second,  to  1  millimeter;  2  inches  of  third,  to  inch,  the  remainder  to  Y&  inch;  2  inches  of 
fourth,  to  %oo  inch,  the  remainder  to  Ys o  inch. 

a  b  c  d  e  f 

Length .  5  10  20  30  50  100  centimeters 

Each . $0.30  .65  1.00  1.35  2.25  7.60 


No.  11-105 

11-106  POLISHED  STEEL  DECIMETER  RULE,  “A  Key  to  the  Metric  System.”  This  rule  is  “one  milli¬ 
meter  thick,  one  centimeter  wide  and  one  decimeter  long.  Its  volume  is  one  cubic  centimeter. 

Its  weight  in  grams  is  the  specific  gravity.”  One  side  is  graduated  to  millimeters  and  centimeters. 

There  is  also  the  statement  that  “one  cubic  decimeter  of  water  weighs  one  kilogram  and  measures 
one  liter.” 

Each  rule  sent  in  metal-bound  leather  case .  .  $0.68 


iijjiii|!ii|iiit|iii|iii|iM|!iyiii!iii|iii!iiyiii|iii|iii|iiijiii|iii|i!i|iiL|iii|iii|iiipii6] 

L.E.  KNOTT  APPARATUS  CO. 

iliiiiliiiiliuTliiiiliiM 


No.  11-130 

11-130  CELLULOID  RULE,  Metric  and  English,  6  inches  long,  with  distinct  black-filled  accurate  divisions' 
showing  clearly  on  the  white  celluloid. 

The  adaptability  of  these  rulers  as  book  markers  and  to  the  vest  pocket  and  their  flexibility  to  mani¬ 
fold  usage  has  fully  warranted  their  popularity  ....  Each  $0.05  Per  doz.  $0.60  Per  100  $4.25 


L.  C.  KNOTT  APPARATUS  CO.,  tooto*.  Him  LABORATORY  EQUIPMENT 

*CCunU  «"d  «»pMj  miiiu'.mtM  of  fUt  IvdtM  CitimtlM  to  «t|p  tonth  m  *w.  >»*y 

|hil  »c»U  li  *up*ito»  to  tho  wood  ««•#.  with  ioi»o»stil*  «ctw'«cy.  ' 

No.  11-135 

11-136  BRISTOL  BOARD  METRIC  RULE,  generally  useful  but  especially  adapted  to  measuring  curved 
surfaces. 

Twenty  centimeters  long,  graduated  to  millimeters  with  margin  of  about  20  millimeters  on  either  end. 

Per  doz.  $0.16.  Per  100  $0.90 


34 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  11-140 

11-140  BRISTOL  BOARD  DIAGONAL  SCALE,  very  carefully  divided,  will  read  accurately  to  H)  millimeter. 

Length  16  centimeters . . . . .  Each  $0.02 

Per  100  1.40 


11-146  BRISTOL  BOARD  COMPARING  SCALE  for  rapid  determinations  of  Metric  and  English  linear 
equivalents. 

Fifty  centimeters  long,  engine  divided .  $0.28 

11-160  PAPER  METRIC  RULE,  20  centimeters  long,  same  as  No.  11-135,  but  of  heavy  bond  paper  .  Per  100  .67 

11-165  PAPER  METRIC  SCALE,  100  centimeters  long,  graduated  to  millimeters.  Accurately  printed  on 

heavy  bond  paper . Each  .07 


No.  11-175 

11-175  STANDARD  METER,  graduated  throughout  entire  length  to  millimeters,  attaining  highest  possible 
accuracy  at  18  degrees  Centigrade. 

Graduated  on  brass  and  included  in  neat  case . Duty  Free  $30.00 

11-177  STANDARD  METER.  Same  as  No.  11-175,  one  decimeter  graduated  to  millimeters,  remainder 
to  centimeters. 

Including  neat  case . . Duty  Free  21.50 

11-186  FOLDING  STEEL  POCKET  RULE,  Metric  and  English  Scales,  engine  divided,  polished  surface 
with  black,  distinct  figures  and  graduations.  Graduated  to  millimeters  on  one  side,  to  inches  and 
sixteenths  on  the  other. 

Length  one  foot,  %  inch  wide,  No.  28  gauge  steel,  folding  to  4  inches. 

Enclosed  in  metal-bound  leather  case .  .60 

STEEL  POCKET  MEASURING  TAPE,  METRIC  AND 
ENGLISH,  spring  wind,  with  stop,  German  silver  case. 
Graduated  to  inches  and  sixteenths  on  one  side,  to  millimeters 

on  the  other.  Length  1  meter .  .96 

- ,  same  as  above,  but  5  meters  long .  4.25 

LINEN  POCKET  MEASURING  TAPE,  METRIC  AND 
ENGLISH,  waterproof-coated  Yi  inch  corded  tape,  in 
brass-bound  case  with  brass  folding  handle,  brass  ring  and 
trimmings. 

Marked  feet  and  inches  one  side;  meters  and  centimeters 

other  side.  Length  10  meters .  .67 

- ,  same  as  above,  but  25  meters  long .  1.35 


No.  11-220 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


35 


MEASURING  INSTRUMENTS 


Calipers,  Micrometers,  Verniers,  Spherometers,  Gauges,  etc. 


Nos.  12-10  to  12-11 


Nos.  12-25  to  12-26 


Nos.  12-27  to  12-28 


12-10  COMBINATION,  OUTSIDE  AND  INSIDE  CALIPERS,  polished  steel.  Length  4  inches  ....  $0.20 

12-11  - ,  same  as  above,  but  6  inches  long .  .25 

For  other  Calipers  see  Index. 

12-25  OUTSIDE  SPRING  CALIPER,  extra  quality  polished  steel  machinist’s  caliper.  Length  4  inches  .  .  .80 

12-26  - ,  same  as  above,  but  6  inches  long .  .90 

12-27  INSIDE  SPRING  CALIPER,  extra  quality  polished  steel  machinist’s  tool.  Length  4  inches  ....  .80 

12-28  - ,  same  as  above,  but  6  inches  long .  .90 


Nos.  12-35  to  12-36  No.  12-95  No.  12-97 


12-35  SPRING  GAUGE  CALIPER,  indispensable  for  the  measuring  of  thicknesses  of  lenses,  sufficiently 
accurate  for  ordinary  laboratory  measurements  of  sheet  metal  and  wire.  Rapid  and  accurate, 


reading  directly  to  %  millimeter.  Measuring  up  to  10  millimeters . $1.60 

12-36  - ,  same  as  above,  but  measuring  up  to  14  millimeters .  1.96 


12-40  CALIPER  GAUGE  for  measuring  thickness  of  plates,  boards,  etc.,  within  range  of  t4o  to  1%  inches,  the 
range  of  the  caliper.  Slide  rod  is  graduated  on  opposite  sides,  one  side  reading  32ds,  the  other 
40ths  of  an  inch.  All  readings  are  made  from  the  top  of  the  knurled  friction  slide,  and  when  in 


operation  the  contact  ends  of  the  gauge  are  brought  together  against  the  object  being  measured, 
the  measuring  rod  may  be  removed  from  the  hook  part  and  the  whole  taken  to  the  light  and  the 

correct  measure  indicated  above  the  friction  slide  easily  taken .  2.60 

12-42  - ,  same  as  above,  but  graduated  in  Metric  System.  Capacity  47  millimeters,  rod  graduated 

on  one  side  into  millimeters,  on  the  other  into  ^  millimeters .  2.60 

12-95  LARGE  DIAL  MICROMETER  CALIPER  for  measuring  the  thicknesses  of  thin  plates,  also  diameters 
of  wires.  This  instrument  consists  of  a  dial,  45  millimeters  diameter,  divided  into  one  hundred  di¬ 
visions.  The  indicator  moves  with  the  screw.  Will  measure  thicknesses  and  diameters  up  to  5 

millimeters  by  Yioo  millimeter.  Handsomely  nickel  plated .  6.65 

12-97  - ,  similar  to  above,  but  provided  with  Friction  Head .  7.16 


36 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


Nos.  12-110  to  12-120 


12-110  FRICTION  HEAD  METRIC  MICROMETER  CALIPER.  It  is  graduated  to  read  to  0.01  mm. 

and  will  measure  up  to  25  mm.  Frame  of  drop  forged  steel  nickel  finished.  The  friction  head  in¬ 


sures  that  all  measurements  are  made  with  the  same  degree  of  pressure . $3.35 

12-116  RATCHET  STOP  METRIC  MICROMETER  CALIPER,  graduated  to  read  to  0.01  mm.  and  will 
measure  up  to  25  mm.  This  caliper  is  similar  to  above  but  with  compensated  speeded  screw  and 

ratchet  stop .  6.00 

12-118  RATCHET  STOP  ENGLISH  MICROMETER  CALIPER,  same  as  above  but  graduated  to  read 

to  0.001  inch  and  will  measure  up  to  one  inch .  6.00 

12-120  RATCHET  STOP  DOUBLE  MEASURE  ENGLISH  MICROMETER  CALIPER,  similar  to  above 

but  can  be  set  to  read  to '0.001  or  0.0001  inch  and  will  measure  up  to  one  inch .  7.40 


No.  12-140 


12-140  SLIDING  CALIPER,  English  and  Metric  measures,  of  boxwood,  with  ivory  sliding  scale.  Will 

measure  up  to  3  inches  by  16ths,  or  up  to  72  millimeters  by  millimeters.  Finer  estimations  possible  $1.10 

Models  for  the  illustrative  demonstration  of  principle  of  verniers  will  be  found  listed  in  Section  10. 

For  accurately  working  model  of  Vernier  Caliper  see  No.  10-70. 


No.  12-166 


12-165  VERNIER  CALIPER,  Metric  measure,  generally  useful  in  outside,  inside,  and  depth  measurements. 

In  use  as  outside  caliper  either  square  or  caliper  jaw  may  be  used.  In  use  as  inside  caliper,  read 
as  for  outside  caliper  and  add  2  millimeters  for  width  of  the  points.  In  reading  for  depth  meas¬ 
urement  use  upper  row  of  figures  and  other  end  of  vernier.  Range  0  to  10  centimeters. 

Made  of  polished  steel . $2.15 


12-160  VERNIER  CALIPER,  Metric  and  English  measures  with  verniers  for  each.  Outside,  inside  and 
depth  measurements  each  possible  with  great  accuracy.  Will  measure  objects  up  to  10.7  centi¬ 


meters  by  millimeter,  or  up  to  inches  by  V128  of  an  inch. 

Made  of  polished  steel  and  provided  with  thumb  knob  and  set  screw . $2.20 

12-161  - ,  same  as  above,  in  neat  leather  case .  2.46 

12  165  - ,  same  as  No.  12-160,  but  with  addition  of  micrometer  screw  adjustment.  In  neat  leather 

case .  3.70 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


37 


No.  12-170 

12-170  TWO-HUNDRED  MILLIMETER  VERNIER  CALI¬ 
PER,  Metric  and  English,  for  outside  measurements 
up  to  200  millimeters,  reading  by  vernier  to  %  milli¬ 
meter;  English  graduations  reading  by  %  inch  up  to 
8  inches. 

This  caliper,  constructed  of  polished  steel,  is  accurately 

graduated.  Jaws  are  55  millimeters  long,  the  movable  one 
provided  with  thumb  friction  slide  which  binds  automatically 
as  soon  as  pressure  of  thumb  is  removed . $4.60 


No.  12-176 

12-176  TWO-HUNDRED  MILLIMETER  OUTSIDE 
AND  INSIDE  VERNIER  CALIPER,  Metric, 
outside  and  inside  measurements  reading  up 
to  200  millimeters  by  Jfo  millimeter.  Caliper 
jaws  11.5  cm.  long,  square  jaws  6  cm.  long. 

Made  of  polished  steel  accurately  graduated 


$4.90 


12-180  METER  ROD  CALIPER  ARMS  WITH  VER¬ 
NIER,  Bonnell  design,  for  use  with  Meter  Stick 
in  assembling  a  Vernier  Caliper  of  large  range. 

These  arms  are  smooth  metal  castings  made 
to  fit  the  standard  Meter  Stick.  One  arm  is 
designed  for  setting  at  some  point  arbitrarily 
selected  as  the  zero  of  the  Meter  Stick,  while 
the  other  carries  two  verniers,  one  to  read  to 
%o  of  an  inch  on  the  English  side,  the  other 
to  read  to  %  millimeter  on  side  with  Metric 
divisions. 

Vernier  arms  only,  neatly  nickeled,  per  pair  .  . 


$2.85 


No.  12-185 


No.  12-190 


12-185  CALIPER  RULE,  for  use  as  a  folding  pocket  rule  and  caliper.  Rapid  caliper  measurement  possi¬ 
ble  where  accuracy  not  greater  than  Vs2  inch  is  desired. 

Two  fold,  brass  bound,  brass  slide,  boxwood  caliper  rule,  slide  graduated  to  Vs2,  rule  to  8ths,  lOths, 
12ths,  and  16ths  of  an  inch.  Total  length  possible,  6  inches . 

12-187  - ,  same  as  above,  but  four  fold  and  12  inches  long . 

12-190  CYLINDROMETER  for  measuring  diameters  of  spheres  and  cylinders  from  4  centimeters  upwards. 

With  directions . . . 

10-76  VERNIER  CALIPER  MODEL  for  demonstrative  and  quantitative  work. 

This  Caliper  Model  is  30  centimeters  long  with  graduations  to  centimeters.  It  is  sufficiently  accu¬ 
rate  for  most  simple  measurements,  for  the  Vernier  will  give  readings  to  one  millimeter. 

Made  of  clear  grain  boxwood,  neatly  finished,  metal  slides,  nickel  plated.  For  illustration,  see  Sec¬ 
tion  10 . 


$0.45 

.55 

.90 


38 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  12-206  No.  12-210 


12-206  SPHEROMETER  for  measuring  curvature  of  lenses,  mirrors,  etc.  Steel  screw  accurately  1  milli¬ 
meter  pitch,  silvered  brass  head  2  inches  in  diameter  graduated  into  50  parts.  Legs  cover  sur¬ 
face  of  25  millimeters  radius.  Will  measure  surfaces  of  5  millimeters  concavity  or  convexity.  Reads 
directly  to  Vso  millimeter,  but  as  divisions  on  head  are  approximately  3  millimeters  apart,  esti¬ 


mations  to  V200  are  readily  possible . .  $6.90 

12-210  SPHEROMETER,  inexpensive,  serviceable  form,  reading  directly  to  Y100  millimeter.  Concave 

measurements  to  5  millimeters,  convex  up  to  15  millimeters .  3.30 


Showingifront  view  of  attachment  Showing  rear  view  of  attachment 

12-226  HARCOURT  UNIVERSALLY-ADJUSTABLE  T-BEAM  MICROMETER  SCREW  for  general 

application  in  laboratory  practice  where  a  micrometer  screw  is  needed. 

The  above  illustration  represents  a  form  of  Micrometer  Screw  originated  by  us  for  attachment  to 
our  No.  6-1000  Harcourt  Universal  T-Beam  Clamp  “A”.  This  attachment  consists  of  a  cast¬ 
ing  carrying  a  swiveled  overhanging  bracket  holding  in  split-post  tension  an  accurately  threaded 
millimeter  screw.  The  whole  is  so  designed  as  to  permit  facing  of  the  screw  in  either  direction  and 
turning  the  screw  in  any  position  in  a  vertical  plane,  and  a  back-and-forth  adjustment  on  the  bed  of 
the  Basic  Clamp.  In  any  of  these  positions  the  attachment,  screw,  and  Basic  Clamp  may  be 
interlocked  by  the  nickel-plated  T  screws  as  one  rigid  instrument. 

The  Head  of  the  screw  is  45  millimeters  in  diameter  and  is  divided  into  100  parts.  The  Screw  is 
accurately  threaded  1  millimeter  pitch,  thus  making  possible  a  reading  to  Vioo  millimeter. 

HARCOURT  UNIVERSALLY-ADJUSTABLE  T-BEAM  MICROMETER  SCREW,  complete  as 
illustrated,  including  Micrometer  Screw  Attachment  and  No.  6-1000  Harcourt  Universal 


T-Beam  Basic  Clamp  “A” . $4.16 

6-1076  HARCOURT  UNIVERSALLY-ADJUSTABLE  MICROMETER  SCREW  ATTACHMENT,  illus¬ 
trated  above  in  connection  with  No.  12-226  .  3.26 

6-1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A”,  illustrated  above  in  connection  with 
No.  12-226 


.94 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


39 


12-230  MOUNTED  MICROMETER  SCREW.  This  is  a  care¬ 
fully  designed  instrument.  The  Stand  is  massive,  pro¬ 
vided  with  three  milled  legs  insuring  stability  and  a 
position  in  true  plumb  with  the  plane  of  the  table. 

The  Screw  is  accurately  threaded  1  millimeter  pitch 
and  is  provided  with  a  head  45  millimeters  in  diameter 
divided  into  100  parts,  thus  reading  to  Yioo  millimeter.  It 
is  mounted  in  a  split-post  tension  in  an  overhanging 
bracket.  Binding  screw  is  provided  for  electrical  con¬ 
nection.  Handsomely  finished  throughout . $2.90 


No.  12-230 


Reverse  Side  No.  12-280 


12-276  AMERICAN  STANDARD  WIRE  GAUGE,  made  of  best  steel,  tempered,  adjusted  and  warranted 
accurate.  Decimal  equivalents  expressed  in  thousandths,  stamped  on  back  opposite  regular  gauge 


numbers.  Sizes  0  to  36  .  .  .* .  .  $2.90 

12-277  - ,  same  as  above,  sizes  5  to  36 .  2.20 


12-280  POCKET  SCREW  AND  WERE  GAUGE  for  measurements  of  wire  as  well  as  machine  and  wood 
screws.  On  front  side  of  left  of  slot,  this  gauge  is  graduated  to  show  all  sizes  of  the  American 
Standard  Screw  Gauge  from  0  to  30;  on  other  side  of  slot,  equivalent  fractions  of  an  inch  are  marked. 

The  edge  of  the  gauge  is  graduated  to  32ds  and  16ths.  The  back  side  is  graduated  on  right  of  slot 
from  17  to  0000  as  the  old  or  English  wire  gauge;  on  the  left  from  15  to  0000  as  the  new  or  Amer¬ 
ican  wire  gauge.  The  angle  cut  in  the  side  allows  the  head  of  a  screw  to  be  placed  in  a  positive  stop 
when  measuring  the  length . # .  2.96 


No.  12-296 

12-295  POLISHED  STEEL  INSIDE  TAPER  GAUGE  for  inside  measurements  of  tubes,  holes,  etc.  Made  of 

hardened  polished  steel  and  about  18  centimeters  long;  will  measure  from  %  to  15  millimeters  .  .  $0.80 


No.  12—300 


12-300  POLISHED  STEEL  OUTSIDE  TAPER  GAUGE  for  outside  measurements  of  rods,  etc.  Made  of 
polished  hardened  steel  about  15  centimeters  long;  will  measure  all  diameters  from  ho  to  10  mil¬ 
limeters  . > .  .  $1.96 


40 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


SQUARES  AND  PROTRACTORS 
SLIDE  RULES 


No.  13-10 


13-10  WALTER  SMITH  SCHOOL  SQUARE.  This  instrument,  simple  in  design,  neat  in  appearance, 
and  universal  in  its  varied  applications  as  rule,  square,  and  protractor,  has  from  its  popularity 
of  35  years’  unquestioned  utility  become  a  standard  laboratory  instrument. 


a 

Length,  inches  7 
Each  ....  $0.06 


b  c 

8  10 

$0.08  $0.12 


No.  13-30 


13  20  PROTRACTOR  TRIANGLE,  Transparent,  30  and  60  degree  angles,  long  leg  5  inches,  divided  to  1 

degree .  $0.60 

13-22  - ,  same  as  above,  but  45  degree  angles . .  .76 

13-30  SQUARE  PROTRACTOR,  Ivory,  6X1%  inches,  graduations  to  single  degrees,  scales  of  %,  %,  %, 

and  1  inch  to  the  foot,  scale  of  chords,  and  diagonal  scale .  2.10 

13-36  SQUARE  PROTRACTOR,  Boxwood,  otherwise  same  as  No.  13-30 . 46 


No.  13-60 

13-60  COMBINATION  BEVELED  PROTRACTOR,  RULE,  and  SQUARE,  protractor  engine-divided  to 
90  degrees,  care  being  taken  to  insure  that  the  zero  is  accurately  at  right  angles  to  the  face  of  the 
head.  An  accurately  graduated,  hardened,  12-inch  adjustable  rule  passes  through  the  revolving 
turret  and  may  be  clamped  at  any  point  by  means  of  the  thumb  nut.  A  small  level  attached  to 
one  side  of  the  head  is  adjustable  to  show  any  degree. 

The  utility  of  this  combination  instrument  is  unquestioned  and  its  purchase  will  never  be  regretted  .  $3.46 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


4i 


No.  13-75 

13-76  PENFIELD  ARM  PROTRACTOR  AND  GONIOMETER  for  use  as  a  rule,  protractor  and  diagonal 
scale.  As  a  rule  will  measure  to  millimeters  up  to  14  centimeters;  as  a  protractor  ^hundredths 
of  an  inch.  It  is  an  accurate  goniometer  for  measuring  plane  angles.  All  graduations  are  engine 


divided  and  all  parts  carefully  and  accurately  assembled.  Complete  with  directions . $0.66 

13-76  PENFIELD  CONTACT  GONIOMETER  for  measuring  angles  of  crystals.  Similiar  to  above  but 

with  the  protractor  arm  opaque  for  a  portion  of  its  length.  Complete  with  directions .  .66 

13-77  PENFIELD  CONTACT  GONIOMETER  for  measuring  internal  angles.  Complete  with  directions.  .66 


No.  13-90 


No.  13-100 


13-90  BRASS  PROTRACTOR,  a  good  serviceable  protractor,  3%  inches  in  diameter,  graduated  in  single 


degrees . $0.12 

13-92  - ,  engine-divided,  best  quality,  4J4  inches  in  diameter,  graduated  in  single  degrees . 27 

13-94  ■ — — ,  engine-divided,  best  quality,  534  inches  in  diameter,  graduated  in  34  degrees .  .48 

13-96  GERMAN  SILVER  PROTRACTOR,  best  quality,  434  inches  in  diameter,  graduated  in  single 

degrees  .  .48 

13-98  - ,  best  quality,  534  inches  in  diameter,  graduated  in  34  degrees . 72 


13-100  TRANSPARENT  AMBER  PROTRACTOR,  semi-circular,  solid,  graduations  and  figures  stamped 
from  engine-divided  plate,  and  clearly  shown  in  black. 


abed 

Graduations  in .  1  34  34  34  degree. 

Diameter .  4  5  6  8  inches. 

Each  $0.18  .40  .85  1.36 


13-106  BRISTOL  BOARD  PROTRACTOR,  printed  from  engine-divided  plate,  diameter  4  inches,  grad¬ 


uated  to  single  degrees,  figures  reading  from  each  end  . . . Per  doz.  .45 

13-107  - - ,  similar  to  above,  but  5  inches  in  diameter  and  graduated  to  34  degree . 12 


BOSTON 


42 


L.  E.  KNOTT  APPARATUS  CO., 


No.  13-135 

13-135LCOMBINATION  PROTRACTOR  AND  DIAGONAL  SCALE,  brass,  silver-finished,  5}/$  inches  long, 
graduations  in  single  degrees,  figures  reading  both  directions.  Diagonal  scale  reading  8  centimeters 
by  %  millimeter .  $0.64 


13-160  METRIC  DIAGONAL  AND  PLOTTING  SCALE  of  boxwood,  15  centimeters  long.  One  side,  double 
diagonal  scale,  —  one  ruled  square  of  2  centimeters  width;  the  other  square,  1  centimeter  width, 
thus  allowing  measurements  up  to  15  centimeters  by  Idoo  millimeter  with  one  and  by  %o  milli¬ 
meter  with  the  other.  The  reverse  side  is  divided  as  a  plotting  scale,  having  reduction  scales  of 

1:4,  1:6,  1:7,  1:8,  and  1:9 .  $0.10 


No.  13-175 


13-176  STUDENT’S  SLIDE  RULE  for  performing  arithmetical  computations  mechanically,  —  multiplica¬ 
tion,  division,  squares,  and  square  roots,  ratio,  etc.  All  are  possible  with  accuracy  to  three  figures. 
This  rule  is  made  of  the  best  quality  of  hard,  gloss-finish  bristol  board,  is  5  inches  long,  with  letters, 


figures  and  graduations  neatly  and  distinctly  shown .  $0.75 

13-180  MANNHEIM’S  SLIDE  RULE,  graduations  on  white  paper  with  protective  coating,  transparent 

indicator  in  metal  frame.  10  inches  long.  With  simple  directions .  1.40 


13-185  SLIDE  RULE  WITH  MAGNIFYING  LENS  ATTACHMENT,  highest  quality  imported  computing 
rule  with  prominent  qualities  which  recommend  it  wherever  a  rapid,  accurate,  and  simple  scale  is 
desired.  Besides  an  extreme  accuracy  of  parts  and  graduation,  this  rule  is  substantially  construct¬ 
ed  of  mahogany  and  inlaid  with  celluloid.  Results  are  obtained  directly,  without  mental  effort 


and  without  computations. 

a 

b 

c 

Length  .  .  .  . 

25 

36 

50  centimeters. 

Duty  Free  .  .  . 

$4.35 

$9.85 

$14.65 

CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


43 


14r-10 

14-16 


14-46 

14-60 


CIRCULAR  PROTRACTORS,  DIVIDING 
ENGINES,  LEVELS,  PLUMBS 


WETMORE’S  TANGENT  SCALE.  This  design  was  suggested  by  the  late  Prof.  E.  W.  Wetmore, 
Normal  College,  Albany.  N.  Y.  It  consists  of  an  engine-divided  bristol  board  dial  3%  inches  in 
diameter,  divided  from  0  to  90  degrees  in  each  quadrant  to  single  degrees.  On  an  outer  circle  tan¬ 
gents  of  corresponding  angles  are  indicated. 

With  this  dial  the  tangents  of  deflection  may  be  noted  directly  instead  of  angles  themselves,  thus 
current  strength  may  be  compared  directly  without  reference  to  any  table . Each 

BRISTOL  BOARD  CIRCULAR  PROTRACTOR,  13  inches  in  diameter,  with  radial  lines  every  10 
degrees  and  further  subdivided  on  two  outer  circles  to  single  and  to  34  degrees. 

This  protractor  may  be  used  to  advantage  in  experiments  on  composition  of  forces  or  on  torsion  Each 


14-20  BRISTOL  BOARD  CIRCULAR 
PROTRACTOR,  4  inches  in 
diameter.  Graduated  in  single 
degrees . Each 

14-26  - ,  3  inches  in  diameter.  Grad¬ 

uated  to  two  degrees  .  .  .  Each 


No.  14-60 


No.  14-46 


$0.08 


.60 


.08 

.06 


BRISTOL  BOARD  QUARTER-CIRCLE  PROTRACTOR,  a  full  quadrant  of  circle  13  inches  in  diam¬ 
eter,  radial  lines  every  10  degrees,  graduated  to  single  and  34  degrees,  figured  from  0  to  90  degrees 
in  both  directions. 

This  protractor  is  used  in  experiments  in  torsion .  $0.09 

ANGLE-GRAPH  for  plotting  any  angle  from  0  to  360  degrees,  excellent  for  plotting  protractors. 

This  instrument  consists  of  a  neatly-finished  wooden  base  on  which  is  mounted  a  brass  ring,  the  upper 
surface  of  which  is  accurately  engraved  from  0  to  360  degrees.  At  the  geometric  center  of  this  circle 
is  fastened  a  brass  rod  with  projecting  screw  at  its  center.  An  index  and  sketching  arm  are  held 
movably  about  this  screw  by  means  of  a  friction  thumb  nut. 

In  use,  the  card  or  paper  which  is  to  be  divided  is  placed  with  its  central  hole  over  the  rod  in  the  central 
part  of  the  apparatus.  By  moving  the  index  arm  any  angle  from  0  to  360  degrees  may  be  plotted. 
Illustration  shows  the  method  of  making  a  circular  protractor. 

As  the  instrument  will  take  in  any  size  up  to  13  inches  diameter,  it  will  be  found  of  great  convenience  in 

any  laboratory .  4.90 


44 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


14-90 


flg  No.  14-90 

CHAPIN-STEPHENS  CARPENTERS’  STANDARD  LEVEL,  first  quality  of  polished  cherry  with 

brass  arch  top-plate  and  side  views.  12  inches  long . . . 


$0.76 


No.  14-96 


1 1-96  WOOD  POCKET  LEVEL,  first  quality,  brass  top,  5  inches  long . $0.40 

14-100  SOLID  ROSEWOOD  LEVEL,  extra  quality,  solid  rosewood,  brass  corners,  top-plate,  ends  and  side  S’*** 
views.  Length  6%  inches . .  1.60 


No.  14-110 


No.  14-116 


14-110  BALANCE  LEVEL,  as  used  on  balances  and  cameras.  Will’indicate  in  all  directions . $1.00 

14-116  TWO-WAY  LEVEL  AND  PLUMB,  valuable  in  plumbing,  squaring,  and  leveling  up  work.  Leveling 
is  indicated  in  every  way  without  moving  the  tool. 

Weighs  3  ounces,  measures  2  X  3  X  M  inch  thick .  1*96 


No.  14-130 


14-126  MERCURY  PLUMB  BOB,  made  from  solid  steel  bored 
and  filled  with  mercury.  Improved  byjjpatented  slot 
device  for  fastening  string  without  tying,  also  by  simple 
effective  device  at  top  for  fastening  end  of  string  after 
winding  up.  Each  bob  is  nickel  plated  and  provided  with 
braided  silk  line.  Weight  6  ounces,  length  5  inches,  diam¬ 


eter  inch . $1.66 

14-130  PLUMB  BOB,  iron,  black  japan  finish .  .12 


No.  14-136 


No.  14-140 


14-136  TWO-FOLD  COMBINATION  RULE,  comprising  in  itself  a  Carpenter’s  Rule,  Spirit  Level,  Try 
Square,  Plumb,  Slope  Level,  Brace  Scale,  Draughting  Scale,  T-Square,  Protractor,  Right  Angled 
Triangle,  and,  with  a  straight  edge,  a  Parallel  Rule. 

Illustration  shows  use  as  a  Level  and  as  a  Try  Square,  the  upper  cut  showing  steel  blade  folded  like 
a  knife  blade  into  part  which  holds  it. 

Made  of  boxwood,  hand-polished  finish,  well  protected  with  heavy  brass  binding.  Folded,  measures 
6  X  1%  X  %  inches .  $2.26 

14-140  POCKET  REFLECTING  LEVEL,  bronze  metal  case,  5  inches  long.  In  leather  case  complete  .  .  .  6.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


45 


BALANCES  AND  WEIGHTS 


The  selection  of  proper  laboratory  balances  together  with  appropriate  sets  of  weights  for  any 
given  laboratory  is  perhaps  one  of  the  most  difficult  tasks  which  an  instructor  is  called  upon  to 
perform.  In  the  hope  that  it  will  be  of  assistance,  we  have  arranged  in  tabular  form  our  very  com¬ 
plete  line  of  Balances  and  Weights,  dividing  them  into  three  arbitrary  groups.  We  believe  that  if 
the  instructor  will  consider  carefully  the  kind  of  work  which  is  to  be  performed  and  will  then  con¬ 
sult  the  tables,  he  will  be  able  to  determine  which  balances  or  combination  of  balances  will  secure 
the  best  results. 

Every  laboratory,  to  be  well  equipped,  should  have  at  least  one  sensitive  Analytical  or  Assay 
Balance.  Balances  of  this  sort,  with  the  weights  to  go  with  them,  will  be  found  in  Group  One. 
In  Group  Two,  we  have  included  balances  of  medium  grade,  that  is,  —  balances  of  reasonable  pre¬ 
cision  where  the  utmost  accuracy  and  sensitiveness  are  not  required.  Group  Three  contains  miscel¬ 
laneous  balances  for  heavy  and  general  laboratory  work. 

In  considering  the  classification  given  below,  it  should  be  borne  in  mind  that  it  is  impossible 
to  draw  a  hard  and  fast  dividing  line  between  each  of  the  three  groups.  In  making  the  classification, 
however,  we  have  been  guided  by  our  years’  experience  in  work  of  this  kind,  and  we  have  taken  the 
risk  of  making  the  experiment  in  the  hope  that  the  tables  will  be  of  assistance  to  teachers  who  are 
not  familiar  with  the  capacities  and  sensibilities  of  the  best  balances  for  general  scientific  work. 
Detailed  descriptions  and  illustrations  will  be  found  on  the  following  pages  under  the  numbers 
specified  in  the  tables  below. 


ASSAY  AND  ANA¬ 
LYTICAL  BALANCES 


Number 

Sensibility 

16-10  .... 

....  Moo  mg. 

16-20  .... 

16-27  .... 

....  ho  mg. 

16-30  .... 

.  .  .  .  ho  mg. 

SCHOOL 


GENERAL  LABORATORY 


BALANCES 


Number 

Sensibility 

16-45  .... 

....  K  mg. 

15-60  .... 

....  y2  mg. 

16-56  .... 

....  y2  mg. 

16-70  .... 

....  1  eg. 

16-76  .... 

....  3  eg. 

16-80  .... 

....  1  eg. 

BALANCES 


Number 

Sensibility 

Number 

Sensibility 

16-100  . 

•  -'A.  eg. 

16-130  . 

16-106  . 

•  •  lA  eg. 

15-136  . 

16-116  . 

.  .  1  mg. 

16-140  . 

.  .  1  eg. 

16-120  . 

.  .  5  mg. 

15-160  . 

.  .  1  oz. 

16-126  . 

.  .  5  mg. 

15- 160 

16- 166  . 

•  •  y*  eg- 

•  •  1  eg. 

HAND  BALANCES 

Nos.  16-200  and  16-206 
Nos.  16-260,  Jolly  Balance 
SPRING  BALANCES 
Nos.  16-300  to  16-376 


WEIGHTS  for  above  Balances 
Nos.  16-10  to  16-100 


WEIGHTS  for  above  Balances 
Nos.  16-10  to  16-100  and 
Nos.  16-160  to  16-180 


WEIGHTS  for  above  Balances 
Nos.  16-300  to  16-386 
IRON  WEIGHTS 
Nos.  16-426  to  16-478 


46 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


BALANCES,  ASSAY  AND  ANALYTICAL 


No.  15-10 


15-10  HIGH-GRADE  ASSAY  BALANCE,  sensibility  x^0  milligram,  agate  edges  and  planes, 

enclosed  in  case. 

Beam  19  centimeters  long,  open  construction,  made  of  aluminum  alloy  possessing  a  high 
tensile  strength  and  a  uniform  density,  divided  into  milligram  divisions  showing 
white  on  black  oxidized  beam.  Edges  and  Planes  are  accurately  ground  from  the  highest 
quality  stones.  Provided  with  simple  Beam  Hoist  and  Pan  Arrest.  Rider  Carriage  is 
operative  over  full  length  of  beam.  Hangers,  of  usual  skeleton  type,  are  made  of  nickel 
silver,  Pans  of  aluminum. 

Balance  is  mounted  on  Double-Drawer  Base  topped  by  Black  Glass  Slab  and  provided 
with  Leveling  Screws.  It  is  enclosed  in  Polished  Mahogany  Case  with  glass  front  slide, 
glass  sides  and  top.  All  parts  are  handsomely  finished  with  a  durable  acid-resisting 
transparent  lacquer. 


Price  from  stock,  $110.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


47 


16-20  KNOTT’S  HIGH-GRADE  ANALYTICAL  BALANCE,  capacity  200  grams,  sensibility 
sV  milligram,  agate  edges  and  planes,  enclosed  in  case. 

Beam  18  centimeters  long,  open  truss  construction,  made  of  aluminum  alloy  possessing  a 
high  tensile  strength  and  a  uniform  density,  is  divided  into  milligram  divisions  filled 
white  on  the  black  oxidized  beam.  Edges  and  Planes  are  ground  from  carefully  selected 
agate  of  highest  quality.  Provided  with  independently  operative  Beam  Hoist  and  Pan 
Arrests,  the  pan  arrests  being  of  special  design  easily  controlled  and  if  desired  self  locking. 
Rider  carriage  of  simple  double-hook  pattern  has  full  clear  sweep  over  entire  length  of 
beam.  Pans  and  Bows  are  of  nickel  silver,  the  pans  being  about  5.5  centimeters  in 
diameter. 

Balance  is  mounted  on  Drawer  Base  topped  by  heavy  Black  Glass  Slab  provided  with  sensi¬ 
tive  crossed  vial  Level  and  Leveling  Screws.  It  is  enclosed  in  Polished  French  Mahogany 
Case  with  front  and  back  glass  slides,  glass  sides  and  top.  It  is  handsomely  and 
durably  finished  with  an  acid-resisting  colorless  lacquer. 

Price  from  Stock,  $117.60 

16-27  THE  “BERLIN”  SHORT  ARM  ANALYTICAL  BALANCE,  capacity  200  grams,  sensi¬ 
bility  ^  milligram,  agate  edges  and  planes,  enclosed  in  case. 

Beam,  15  centimeters  long,  open  construction,  is  divided  into  Aj  milligram.  Simple  Rider 
Carriage  operates  over  half  of  beam.  Agate  Edges  and  Planes  carefully  ground  from 
selected  stones.  New,  effective  Pan  and  Beam  Arrestment  operative  simultaneously. 
Bows  and  Pans  made  of  nickel,  pan  5  centimeters  in  diameter  being  attached.  ~ 

Balance  is  mounted  on  Black  Glass  Slab  provided  with  quick-acting  Circular  Level  and 
Leveling  Screws.  It  is  enclosed  in  Polished  Mahogany  Case  with  glass  front  and  back 
slides,  glass  sides  and  top.  It  is  finished  with  a  protective  acid-resisting  lacquer. 

This  balance  meets  all  requirements  for  accurate  and  rapid  weighings. 

Price  from  Stock,  $65.00 


48 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTJON 


No.  16-30 


15^30  HIGH-GRADE  ANALYTICAL  BALANCE,  capacity  100  grams,  sensibility  TV  milligram, 
agate  edges  and  planes,  enclosed  in  case. 

Beam,  15  centimeters  long,  open  construction,  made  of  aluminum  alloy  possessing  high 
tensile  strength  and  uniform  density,  is  divided  the  full  length  from  0  at  center  into  ^ 
milligrams.  Edges  and  Planes  carefully  ground  from  the  highest  quality  selected  agate. 

Independently  operative  Beam  Hoist  and  Pan  Arrest.  Simple,  single  hook  Rider  Adjust¬ 
ment  has  full,  clear  sweep  of  entire  length  of  beam.  Pans  and  Bows  are  of  nickel,  pans, 
7.5  centimeters  diameter,  being  attached  to  bows. 

Balance  is  mounted  on  Drawer  Base  provided  with  quick-acting  Circular  Level  and  Level¬ 
ing  Screws.  It  is  enclosed  in  Polished  Mahogany  Case  with  front  and  back  glass  slides, 
glass  sides  and  top.  It  is  Heavily  Platinum  Plated  throughout,  thus  insuring  against 
corrosion. 

We  call  especial  attention  to  the  quality  of  the  case  of  this  balance.  It  is  of  selected  mahog¬ 
any,  carefully  seasoned  and  polished  to  a  piano  finish. 

In  that  all  metal  parts  are  heavily  platinum  plated,  the  balance  is  proof  against  corro¬ 
sion.  Its  durability  as  an  accurate  analytical  balance  is  permanently  assured. 


Price  from  Stock,  $62.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


49 


SCHOOL  BALANCES 


No.  16-45  No.  16-60 


15-45  “HARCOURT  SPECIAL”  QUICK-ACTING  BALANCE,  capacity  100  grams,  sensibility 
X  milligram,  agate  edges  and  planes,  enclosed  in  case. 

Beam,  18  centimeters  long,  open  construction,  is  divided  into  K  milligrams  on  one  side  of 
central  knife  edge.  Agate  Edges  and  Planes  carefully  ground  from  selected  stones. 
Simple  Beam  Hoist  and  Rider  adjustment.  Pans,  8.5  centimeters  in  diameter,  are  de¬ 
tachable. 

Balance  is  mounted  on  Drawer  Base,  provided  with  Plumb  Bob  and  Leveling  Screws. 
It  is  enclosed  in  Polished  Mahogany  Case  with  glass  front  slide,  glass  sides,  top  and  back. 

This  balance  was  designed  especially  for  us  and  we  have  no  hesitancy  in  commending  it  as 
combining  all  the  essential  qualifications  of  a  high-grade  balance  at  a  cost  within  the 
range  of  any  educational  institution. 

Price  from  Stock,  $42.25.  Duty  Free, . 


15-50  KNOTT’S  NORMAL  BALANCE,  capacity  100  grams,  sensibility  milligram,  agate  edges 
and  planes,  enclosed  in  case. 

Beam,  21  centimeters  long,  open  construction.  Edges  and  Planes  of  carefully-ground 
agate.  Simple,  effectively  operating  Beam  Hoist,  detachable  8  centimeter  pans. 

Balance  is  mounted  on  Drawer  Base,  provided  with  Plumb  Bob  and  Leveling  Screws. 
It  is  enclosed  in  Polished  Mahogany  Case  with  front  and  back  glass  slides,  glass  sides  and 
top. 

The  balance  is  lacquered  throughout  and  being  made  especially  for  us  by  a  noted  manu¬ 
facturer  we  unhesitatingly  recommend  its  qualities. 

Price  from  Stock,  $35.00.  Duty  Free, . 


50 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


15-55  HARCOURT  SCHOOL  BALANCE,  capacity  50  grams,  sensibility  Y  milligram,  steel  edges 
and  planes,  enclosed  in  case. 

Beam,  20.5  centimeters  long,  closed  construction.  Edges  and  Planes  of  steel  accurately 
ground  and  polished.  Simple  Beam  Hoist.  Detachable  6.5  centimeter  Pans. 

Balance  is  mounted  on  Drawer  Base,  provided  with  Plumb  Bob  and  Leveling  Screws.  It 
is  enclosed  in  Polished  Mahogany  Case,  with  glass  front  slide,  glass  sides  and  back, 
lacquered  throughout. 

This  balance  is  well  made  throughout  and  is  dependable  in  all  of  its  qualifications. 

Price  from  Stock,  $29.50.  Duty  Free, . 


No.  15-70  No.  15-80 


15-70  EQUAL  ARM  BALANCE,  capacity  20  grams,  sensibility  1  centigram,  polished  steel 
edges  and  planes,  mounted  on  drawer  base. 

Beam,  23  centimeters  long,  closed  construction  with  adjusting  screws,  is  provided 
with  eccentric  lift.  Pans,  7.5  centimeters  diameter.  Balance  is  mounted  on 
Polished  Mahogany  Drawer  Base,  is  polished  throughout,  with  lacquer  and 
nickel-plate  finish . $12.00 

15-75  - ,  similar  in  design  to  No.  15-70,  but  smaller  and  less  sensitive.  Beam  15  centi¬ 
meters  long,  pans  6  centimeters  in  diameter,  sensibility  3  centigrams  ....  8.60 

15-80  EQUAL  ARM  BALANCE,  reliable  for  small  weighings.  Beam  15  centimeters  long. 

Pans  7.5  centimeters  in  diameter,  Lever  Lift.  Balance  is  nickel-plated  throughout 
and  is  mounted  on  Polished  Oak  Drawer  Base .  3.75 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


5i 


PHYSICAL  LABORATORY  BALANCES 


No.  15-100 


16-100  “THE  BOSTON”  LABORATORY  BALANCE,  capacity  2000  grams,  sensibility  3^ 
centigram,  polished  steel  knife-edges  and  planes,  mounted  on  polished  mahogany 
base  provided  with  leveling  screws. 

Beam,  32  centimeters  between  knife-edges,  of  open  truss  construction,  is  divided  entire 
length,  with  0  at  the  left.  Rider  of  improved  design  is  attached  movably  to  beam. 
Edges  and  Planes  are  of  polished  steel  accurately  adjusted.  Pans,  14  centimeters  in 
diameter,  are  detachable  from  stirrups.  Beam  Hoist  of  simple  eccentric  type,  operated 
by  knurled  head. 

This  balance  is  mounted  on  highly  Polished  Mahogany  Base  provided  with  Leveling 
Screws.  It  is  handsomely  finished  and  coated  with  protective  lacquer.  Pans  are 
nickel-plated. 

Each  balance  is  provided  with  accurate  counterpoise  to  take  place  of  one  of  the  stirrups 
when  balance  is  used  in  hydrostatic  work. 

Prospective  purchasers  of  a  balance  of  this  type  will  do  well  to  investigate  our  make  be¬ 
fore  deciding  upon  another.  Our  confidence  in  our  product  is  such  that  we  will  gladly 
offer  every  facility  for  comparative  tests  on 

1.  Beam  stability  and  uniform  density. 

2.  Careful  mechanical  construction  and,  therefore,  accuracy  and 

sensibility. 

3.  Design. 

4.  Finish. 


Price  from  Stock,  $22.00 


52 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  16-106 


15-105  THE  “BAY  STATE”  LABORATORY  BALANCE,  capacity  2000  grams,  sensibility  y2 
centigram;  polished  steel  knife-edges  and  planes,  mounted  on  substantial  metal  base. 

Beam,  32  centimeters  between  knife  edges,  of  open  truss  construction,  is  divided  the 
entire  length  from  0  at  the  left.  Improved  rider  is  attached  movably  on  beam  but 
cannot  be  detached.  Edges  and  Planes  are  of  polished  steel.  Pans,  14  centimeters 
in  diameter,  are  detachable  from  stirrups. 

The  support  for  this  balance  consists  of  a  neatly  japanned  metal  base  to  which  is  mounted 
a  nickel-plated  upright  which  carries  the  beam.  This  upright  is  provided  with  a  damper, 
which,  operated  by  a  thumb  screw,  dampens  the  vibrations  that  rapid  readings  may 
be  taken.  A  plumb  bob  fastened  to  the  upright,  and  leveling  screws  in  the  base,  afford 
ample  adjustments  for  leveling. 

Each  balance  is  furnished  with  an  adjustable  shelf  for  work  in  hydrostatics. 

Price  from  Stock,  $14.35.  Duty  Free, . 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


53 


No.  15-115 


No.  16-126 


15-116  SPECIFIC  GRAVITY  BALANCE,  capacity  200  grams,  sensibility  1  milligram,  polished  steel  edges 
and  planes.  Beam  14  centimeters  long,  of  aluminum  alloy.  Beam  lift,  detachable  pans  7  cen¬ 
timeters  in  diameter  with  removable  papier-machejpan  linings. 

Each  balance  is  mounted  as  illustrated  and  is  supplied  with  a  Thermometer  Plummet  (Reimann’s 
patent),  two  Counterpoises  of  10  and  5  gram  weight,  and  with  a  glass  Hydrometer  Jar.  Duty  Free 


16-120  WESTPHAL’S  SPECIFIC  GRAVITY  BALANCE,  for 

rapid  determinations  of  specific  gravity  of  liquids 
up  to  the  fourth  place  of  decimals. 

All  parts  of  this  balance  are  most  carefully  made.  In  use 
they  are  mounted  on  a  polished  mahogany  box,  as  il¬ 
lustrated,  which  serves  as  a  storage  and  carrying  case. 

Each  balance  is  furnished  with  an  accurate  Thermometer 
(Reimann’s  patent),  Counterpoise,  Jar  and  eight  Riders. 

Price  from  Stock  .  .  . 

Duty  Free . 

15-125  KNOTT’S  HYDROSTATIC  BALANCE  with  ADJUSTA¬ 
BLY  SUSPENDED  BEAM.  This  balance  is  made 
according  to  our  specifications  by  a  well-known  European 
balance  maker.  Capacity  250  grams,  sensibility  5 
milligrams,  polished  steel  edges  and  planes.  Beam 
25  centimeters  long  graduated  the  whole  length  with 
zero  at  the  center.  Beam  hoist  consists  of  pulley  and 
capstan.  Three  counterpoised  stirrups  with  attached 
pans  are  supplied;  two  stirrups  are  of  the  same  size 
and  the  third,  somewhat  shorter,  permitting  with  beam 
raised,  a  clear  space  of  23  centimeters  below  the  scale 
pan.  Mounted  on  polished  mahogany  base.  Duty  Free  .  .  . 


No.  16-120 


54 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  15-130 


No.  15-140 


16-130  HYDROSTATIC  BALANCE,  prismatic-steel  knife-edges,  mounted  on  japanned,  round,  iron  base. 

Beam  834  inches  long  is  supported  on  polished  steel  knife-edges  on  planes  held  in  a  stirrup  attached 
to  the  top  of  a  brass  rod  which  telescopes  into  a  brass  tube. 

The  two  pans  attached  by  chains  to  hooks  near  the  ends  of  the  beam  are  4  inches  in  diameter  and 
are  heavily  nickel-plated.  One  pan  is  suspended  by  short  lengths  of  chain  and  is  provided  with  hook 
for  experiments  in  specific  gravity.  The  beam  may  be  elevated,  giving  an  adjustment  of  from  6 
to  14  inches  from  the  top  of  the  table.  This  balance  will  be  found  satisfactory  for  experiments 
in  specific  gravity.  It  is  of  the  best  workmanship  and  handsomely  finished  throughout . $  6.90 

15-135  SPECIFIC  GRAVITY  BALANCE,  similar  in  design  to  No.  15-130,  but  smaller.  Beam  is  734  inches 

long,  pans  2 3 4  inches  diameter,  adjustment  of  hook  possible  from  434  to  10  inches .  4.40 

15-140  TRIPLE  BEAM  BALANCE,  for  rapid  and  accurate  weighings  in  Physical  or  Chemical  Laboratory. 
Capacity  111  grams,  sensibility  (guaranteed)  1  centigram. 

As  name  “Triple  Beam”  describes,  this  balance  is  constructed  with  three  beams  so  placed  one  over 
the  other  as  to  secure  uniform  weight  upon  the  knife-edge.  The  lower  beam  has  a  capacity  of  100 
grams  by  10-gram  divisions;  the  middle  beam,  10  grams  by  single  grams;  the  upper  beam,  1  gram 
by  34  and  34oo  gram,  each  beam  carrying  an  accurately  adjusted  weight  attached  movably  to  it. 

Base  is  substantially  made  of  cast  iron  neatly  japanned  and  is  provided  with  sensitive  spirit  level 
and  leveling  screw.  Upright,  neatly  nickel-plated,  carries  an  adjustable  support  for  the  receptacle 
in  specific  gravity  experiments.  At  top  of  upright  there  is  a  knurled  head  which  operates  a  sim¬ 
ple  lift  for  beam  when  not  in  use.  Pan,  10  centimeters  in  diameter,  is  detachable.  Price  from  stock  14.00 


15-150  PLATFORM  COUNTER  SCALE  for 

use  on  a  counter  or  low  platform.  This 
scale  is  the  standard  platform  scale 
with  low  pillar.  A  multitude  of  uses  will 
be  found  for  it  in  any  laboratory.  Ca¬ 
pacity  200  pounds  by  1  ounce.  Plat¬ 
form  measures  1034  by  14  inches. 

Complete  with  Weights . 


$17.60 


No.  16-150 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


55 


The  form  of  this  Trip  Scale  is  such  as  to  make  it  the  most 
convenient  balance  for  laboratory  work. 


DESIGN.  The  center  of  gravity  of  the  moving  system  is 
properly  placed.  Made  of  rigid  cast  metal,  it  will  stand  heavy 
loads  without  error.  The  knife-edges  are  held  rigidly  in  position 
and  cannot  change.  The  equal  length  of  the  arms  is  absolutely 
assured. 


No.  16-165 


No.  16-180 


NEW  FEATURES  which  have  been  added  are  noteworthy  in  the  field  of  Balance  Construction: 

METHOD  OF  READING.  By  reference  to  the  cut,  it  will  be  noted  that  we  have  adopted  the  straight 
line  indicator  which  eliminates  all  errors  due  to  parallax. 

LONG  GRADUATED  RIDER  ARM.  The  length  of  the  rider  arm  has  been  greatly  increased  so 
as  to  give  a  wide,  open  scale  with  a  range  of  10  grams  in  %  gram  divisions. 

SPECIFIC  GRAVITY  HOOK.  For  convenience  in  Specific  Gravity  Experiments,  a  hook  is  securely 

attached  to  each  platform  post. 

ADJUSTMENT.  The  position  of  the  adjusting  screw  is  properly  placed  to  avoid  accidental  displacement. 


16-160 

16-166 


16-180 


16-182 


6-1160 

16-186 

16-186 

16-187 


STEEL  BEARING  HARCOURT  TRIP  SCALE . $5.76 

AGATE  BEARING  HARCOURT  TRIP  SCALE.  This  scale,  in  addition  to  above  important  im¬ 
provements,  is  provided  with  six  agate  planes  accurately  secured  and  set  in  rigid  castings.  The 
agate  holders  are  cut  with  such  a  degree  of  nicety  that  we  are  able  to  guarantee  the  planes  not 
to  loosen  or  change  position  even  to  Vlooo  of  an  inch .  6.66 

THE  HARCOURT  INTERLOCKING  METAL  TRIP  SCALE  SUPPORT  for  use  on  the  table  with 
above  trip  scales  in  specific  gravity  experiments. 


The  design  of  the  various  parts  of  this  support  is  such 
that  danger  of  balance  falling  from  support  or  being 
knocked  from  same  is  wholly  obviated.  The  Har- 
court  Special  H-Base  is  designed  so  that  the  6X8 
inch  battery  jar  or  other  containing  vessel  may  be 
placed  directly  under  the  suspending  hook.  Support 
only . 

CROSS  BAR  T-BEAM  ATTACHMENT  TRIP  SCALE 
SUPPORT,  for  use  with  our  T-Beam  Basic  Clamp 
No.  5-1150  in  supporting  the  trip  scales  above  to  the 
cross  bar  of  Standard  Physics  Table  No.  1-100.  This 
attachment  is  readily  secured  to  the  No.  5-1150  clamp 
and  permits  of  use  of  trip  scale  crosswise  or  lengthwise 
of  the  table,  in  addition,  enabling  one  to  readily  ad¬ 
just  the  height  of  balance  from  top  of  table. 

Complete  without  T-Beam  Basic  Clamp  No.  5-1150.  . 

HARCOURT  T-BEAM  BASIC  CLAMP  “B”  as  re¬ 
quired  for  use  with  above  attachment  ..>..... 

WOODEN  SPREADER  FOR  HARNESS,  after  Tur¬ 
ner  and  Hersey  (Exp.  M041) . 

WOODEN  COUNTERPOISE,  after  Turner  and  Hersey 
(Exp.  M041) . 

BRASS  S-HOOK,  after  Turner  and  Hersey  (Exp. 

M041) . 


1.66 
.12 
.12 

.08  No.  16-182 


56 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


15-200  HAND  BALANCE,  first  quality  stand¬ 
ard  hand  balance,  inch  beam, 

hardened  steel  knife-edges;  horn 
pans  3  inches  diameter;  beam,  lac¬ 
quered  brass  . 

15-205  - ,  similar  to  above,  but  less  expen¬ 
sive  in  construction . 

5-915  HAND  BALANCE  SUPPORT  OR 

CLAMP  for  use  on  a  tripod  stand  as  a 
support  for  hand  balances,  affording 
a  simple  but  effective  method  of 
adjusting  the  position  of  the  pans 
»  to  various  conditions  in  experi¬ 

ments  in  specific  gravity.  For  il¬ 
lustration  see  Section  5 . 


15-250  IMPROVED  JOLLY  BALANCE.  This  is  a  design  utilizing  our  No. 

22-130  Universal  Stand  used  so  extensively  in  Topic  II.  To  this  stand 
are  clamped  special  clamp  castings,  one  to  hold  the  stirrup  to  which  the 
spring  is  attached,  another  (No.  5-895)  for  clamping  the  mirror  scale, 
another  (Platform  No.  6-627)  for  supporting  the  glass  vessel.  The 
adjustments  possible  with  this  structure  and  the  ready  adaptability  of 
the  various  parts  to  other  uses  will  be  noted. 

Jolly  Balance  complete  as  illustrated,  with  two  aluminum  scale  pans, 
plummet,  two  springs,  —  one  for  high  and  one  for  low  tension,  and 
accessories  noted  above,  except  glass  vessel . 

15-251  JOLLY  BALANCE  SPRING  for  low  tension . 

15-252  - ,  for  high  tension . 


$2.25 

1.65 


7.85 

.50 


.50 


No.  15-250 


SPRING  BALANCES 


Nos.  15-300  to  16-315 


Our  spring  balances  are  constructed  for  us  according  to  our  specifications  and  we  have,  therefore,  been  able  to 
embody  important  features  not  found  in  stock  designs.  One  of  our  specifications  in  our  orders  to  the  manufacturer 
is  that  the  tension  of  the  spring  must  be  uniformly  accurate.  Graduations  are  distinct  and  all  parts  are  Carefully  made 
throughout.  Handsomely  finished  in  nickel  and  black  finish.  All  our  balances  have  double  pointer  for  accurate 
readings  in  both  horizontal  and  vertical  positions.  In  use  in  vertical  position  the  weight  of  the  hook  is  automati¬ 
cally  deducted  by  the  width  of  the  pointer. 

•  • 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


57 


1&-300 

16-305 

16-310 

16-316 


FLAT  BACK  SPRING  BALANCE,  double  scale,  250  grams  by  10-gram  divisions’,  and  8  ounces 


by  34-ounce  divisions . $0.80 

— — ,  double  scale,  500  grams  by  20-gram  divisions,  and  16  ounces  by  J^-ounce  divisions.  .  .  1.00 

- ,  double  scale,  2000  grams  by  25-gram  divisions,  and  64  ounces  by  34-ounce  divisions.  .  .  .46 

- ,  double  scale,  15  kilograms  by  200-gram  divisions,  and  30  pounds  by  J^-pound  divisions.  .  .  1.66 


No.  16-332 


16-330  TEN-POUND  LABORATORY  DYNAMOMETER  in  nickel-plated  brass  tube.  English  system 


only,  10  pounds  by  34  pound.  Length,  exclusive  of  hook  and  ring,  3%  inches . $1.40 

16-332  TWENTY-POUND  LABORATORY  DYNAMOMETER  in  nickel-plated  brass  tube.  English 

system  only,  20  pounds  by  34  pound.  Length,  exclusive  of  hook  and  ring,  8  inches .  2.16 

16-334  SIXTY-POUND  LABORATORY  DYNAMOMETER  in  nickel-plated  brass  tube.  English  sys¬ 
tem  only,  60  pounds  by  34  pound.  Length,  exclusive  of  hook  and  ring,  934  inches .  3.20 


No.  16-366 


16-360  SPRING  BALANCE  CRADLE,  for  holding  a  spring  balance  in  a  flat  position.  Made  entirely  of 


metal  for  double-scale  balances  Nos.  16-300  to  16-310 . $0.16 

16-366  - ,  same  as  above,  but  made  entirely  of  wood  for  spring  balance  No.  16-316 . 46 


No.  15-376 


16-375  RINTOUL’S  SPRING  DYNAMOMETER,  open  movement,  an  effectively  working  spring  balance. 

Consists  of  the  usual  form  spring  resting  in  a  groove,  with  hook  for  attaching  to  scale  pan,  etc.  A 
double  indicator  allows  reading  from  scale  from  1  gram  up  to  250  grams,  or  from  34  ounce  up  to 
8  ounces,  with  balance  in  either  horizontal  or  vertical  position.  An  adjustment  at  top  by  which 
the  spring  can  be  reset  allows  for  variations  in  the  zero  reading,  providing  spring  should  become 
permanently  elongated.  Made  wholly  of  metal  and  handsomely  finished  in  bright  nickel  and 
japan . $2.50 


58 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  i 


WEIGHTS 

STANDARD  NORMAL  WEIGHTS 

The  weights  under  this  heading  are  adjusted,  with  the  utmost  nicety  attainable,  to  the  standard 
which  has  been  verified  by  the  “Bureau  International  des  Poids  et  Mesures”  at  0°  in  vacuo,  to  an 
accuracy  of  0.01  milligram. 


No.  16-10 


16-1Q  STANDARD  NORMAL  KILOGRAM,  constructed  of  the  hardest  attainable  drawn-brass 
rod  turned  to  shape,  and  trimmed  by  long  and  tedious  work  to  practical  accuracy, 
the  final  finest  adjustment  being  then  secured  by  an  adjusting  pin  ground  into  the  top, 
and  a  gold  plating. 

Enclosed  in  polished  mahogany,  plush-lined  lock  case. 

Duty  Free,  $32.50 

16-15  STANDARD  NORMAL  GRAM,  constructed  from  a  single  piece  of  platinum-iridium, 
trimmed  and  adjusted  with  the  same  nicety  as  the  above. 

Enclosed  in  polished  mahogany,  plush-lined  lock  case. 

Duty  Free,  $16.75 

16-20  STANDARD  NORMAL  WEIGHTS,  each  weight  constructed  from  the  hardest  attainable 
hard-drawn  brass  rod  turned  to  shape,  trimmed  and  adjusted  with  the  same  pains¬ 
taking  accuracy  as  the  above.  Fractional  weights  are  of  platinum,  adjusted  to  finest 
possible  accuracy.  Set  from  1  milligram  up  to  100  grams,  enclosed  in  polished  mahogany, 
plush-lined  case. 


Duty  Free,  $38.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


59 


PRECISION  AND  ANALYTICAL  WEIGHTS 


The  following  weights,  Nos.  16-50  to  16-100,  are  adjusted^to  the  highest  degree  of  accuracy.  Turned  from  hard- 
drawn  brass  rod,  they  are  more  durable  than  cast  weights  andjmuch  superior  from  standpoint  of  permanent  accuracy. 


No.  16-60 


16-60  PRECISION  WEIGHTS,  gpld-plated.  Fractional  weights  500  to  10  milligrams,  are  of  platinum, 
the  smaller  ones  of  aluminum.  One  milligram  up  to  50  grams,  with  ivory-pointed  forceps  and 
camel’s-hair  brush  in  velvet-lined,  highly  polished  mahogany  case  with  removable  lid. 

Price  from  Stock  $12.00 
Duty  Free . 


16-62  - ,  same  as  above,  but  1  milligram  up  to  100  grams . 20.00 

16-64  -  — ,  same  as  above,  but  1  milligram  up  to  200  grams . Duty  Free  .  .  . 


16-70  ANALYTICAL  WEIGHTS,  gold-plated,  similar  to  Nos.  16-60  to  16-64,  but  of  different,  though  as 
accurate  adjustment,  and  enclosed  in  case  of  cheaper  construction.  One  milligram  up  to  50  grams 

Duty  Free  .  .  . 

16-72  - ,  same  as  above,  but  1  milligram  up  to  100  grams  . . Duty  Free  .  .  . 


Nos.  16-80  to  16-100 


16-80  ANALYTICAL  WEIGHTS,  single  weights,  gold  plated,  minutely  adjusted,  as  used  in  sets  Nos.  16-70  to  16-72. 

abcdefghi  j 

Size,  grams  1  2  5  10  20  50  100  200  500  1000 

Each  .  .  .  $0.60  $0.76  $0.96  $1.36  $1.60  $1.90  $2.40  $3.10  $4.26  $6.86 


16-90  ANALYTICAL  FRACTIONAL  WEIGHTS,  single  weights,  —  500  to  10-milligram  weights  of  platinum; 
5  to  1-milligram  weights  of  aluminum,  as  used  in  sets  Nos.  16-70  to  16-72. 


a  b  c 

Size,  milligrams  12  5 

Each . $0.20  $0.20  $0.20 

16-100  ANALYTICAL  RIDER  WEIGHTS,  single 

a 

Size,  milligrams  .  .  1 

Each  . $0.40 


d 

e 

f 

g 

h 

10 

20 

50 

100 

200 

$0.30  $0.35 

$0.45 

$0.75 

$1.10 

weights  of  solid  gold. 

b 

c 

d 

e 

2 

5 

10 

12 

$0.40 

$0.25 

$0.25 

$0.25 

500 

$1.95 


For  other  SINGLE  WEIGHTS,  FRACTIONAL  WEIGHTS,  and  RIDERS,  see  Nos.  16-350  to  16-370. 


6o 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


TECHNICAL  WEIGHTS 


The  weights  under  this  heading  are  intended  for  technical  purposes.  They  are  carefully  ad¬ 
justed,  but  not  to  the  same  degree  of  accuracy  as  our  Precision  and  Analytical  Weights.  Single 
weights  are  made  of  hard-drawn  brass  rods  turned  to  weights,  neatly  lacquered  and  then  adjusted. 


No.  16-154  No.  16-178 


16-150  WEIGHTS,  1  milligram  to  20  grams,  in  highly-polished  mahogany  case  with  cover.  Fractional 
weights,  500  to  10  milligrams  of  German  silver,  5  to  1  milligram  of  aluminum;  with  forceps,  under 


stout  glass  plate . $3.95 

16-161  - ,  same  as  above,  but  1  milligram  to  50  grams .  4.46 

16-152  - ,  same  as  above,  but  1  milligram  to  100  grams .  5.76 

16-153  - ,  same  as  above,  but  1  milligram  to  200  grams . Duty  Free  6.40 

16-154  - ,  same  as  above,  but  1  milligram  to  500  grams . Duty  Free  6.90 


16-176  WEIGHTS,  same  quality  as  above,  but  in  highly  polished  pear-wood  block,  fractions  under  a  glass 


cover.  One  milligram  up  to  20  grams;  with  forceps .  2.15 

16-176  ,  same  as  above,  but  1  milligram  up  to  50  grams .  2.95 

16-177  — - — ,  same  as  above,  but  1  milligram  up  to  100  grams .  3.40 

16-178  — — ,  same  as  above,  but  1  milligram  up  to  200  grams .  4.16 

16-179  — - — ,  same  as  above,  but  1  milligram  up  to  500  grams .  6.85 

16-180  ,  same  as  above,  but  1  milligram  up  to  1000  grams .  8.76 


No.  16-227  No.  16-230 


16-225  ALL-IVORY  FORCEPS,  11  centimeters  long,  best  quality . $1.40 

16-227  IVORY-POINTED  BRASS  FORCEPS,  11  centimeters  long . 75 

16-230  LACQUERED  BRASS  FORCEPS,  10  centimeters  long .  .16 

16-260  FLAT  CAMEL’S-HAIR  BRUSH,  y2  inch  wide,  best  quality . 16 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


61 


GENERAL  LABORATORY  WEIGHTS 


Nos.  16-300  to  16-302  Nos.  16-310  to  16-316 


No.  16-327 


16-300  BRASS  WEIGHTS,  1  centigram  up  to  50  grams,  in  polished  hardwood  box  with  cover . $1.86 

16-302  - ,  same  as  above,  1  centigram  up  to  100  grams .  2.30 

Note.  We  recommend  these  weights  in  covered  boxes,  since  there  is  less  risk  of  loss  and  the  weights  are  kept  free  from  dust. 

16-310  BRASS  WEIGHTS,  same  quality  as  above,  but  in  block;  1  centigram  up  to  20  grams  .......  1.20 

16-312  - ,  same  as  above,  1  centigram  up  to  50  grams .  1.40 

16-316  - ,  same  as  above,  1  centigram  up  to  100  grams .  1.86 

16-326  BRASS  WEIGHTS,  same  quality  as  above,  but  without  fractional  weights,  1  gram  up  to  500  grams  3.96 
16-327  ,  same  as  above,  1  gram  up  to  1000  grams .  5.60 


Note.  The  use  of  No.  16-325  or  16-327  is  recommended  with  Trip  Scale  No.  15-160  or  15-165,  as  no  smaller  weight  than 
1  gram  is  needed. 


Nos.  16-360  to  16-366 


16-360  SEPARATE  BRASS  WEIGHTS,  as  used  in  “General  Laboratory  Weights.” 


a  b  c  d  e  f?|  g  h  i  j 

Size,  grams  1  2  5  10  20  50  100  200  500  1000 

Each  .  .  .  $0.07  $0.08  $0.10  $0.12  $0.16  $0.24  $0.36  $0.68  $1.16  $2.26 

wiS 

16-366  SEPARATE  FRACTIONAL  WEIGHTS  of  German  silver,  as  used  in  “General  Laboratory  Weights.” 

abcdefghi 
Size,  milligrams  ...  1  2  5  10  20  50  100  200  500 

Each . $0.06  $0.06  $0.06  $0.06  $0.06  $0.06  $0.06  $0.06  $0.06 


No.  16-370 

16-360  FRACTIONAL  WEIGHTS,  German  silver  and  aluminum,  one  each  listed  under  No.  16-366,  with 

duplicates  of  the  2,  20  and  200-milligram  weights.  In  cardboard  box . Per  Set  $0.66 

16-370  FRACTIONAL  WEIGHTS,  German  silver,  as  listed  under  No.  16-360,  but  in  neat  wooden,  slide- 

top  box  with  separate  compartment  for  each  size  weight .  L24 

16-380  AVOIRDUPOIS  BRASS  WEIGHTS,  Va  ounce  up  to  1  pound.  In  block .  4.40 

16-386  TROY  BRASS  WEIGHTS,  V2  grain  up  to  1  ounce.  This  set  is  highly  recommended  for  its  peda¬ 
gogic  value  in  teaching  the  relation  of  the  Troy  system  and  the  other  systems  of  weights  ....  1.90 


62 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


IRON  WEIGHTS 


Nos.  16-425  to  16-430 


Iron  weights  are  now  practically  universally  used  in 
mechanical  powers  experiments,  with  sonometers,  etc. 


No.  16-440 


16-425  OCTAGONAL  IRON  WEIGHTS,  52 grams  up  toll  kilogram . Per  Set  $1.40 

16-430  - ,  5  grams  up  to  2  kilograms . Per  Set  2.16 


16—440  DISC  IRON  WEIGHTS,  1  ounce  up  to  16  ounces. 

Set  comprises  weights  of  1,  2,  4  and  8  ounces  with 
duplicate  of  the  1  ounce . 

16-450  INTERHOOKING  LABORATORY  WEIGHTS  for 

general  utility  in  the  Physical  Laboratory  in 
the  study  of  mechanical  advantages  of  simple 
machines. 

These  weights  are  accurately  adjusted  from  cast 
hexagonal  blocks  of  iron,  of  a  design  permitting 
the  attaching  of  one  weight  to  the  other  by  a  hook, 
the  top  of  one  to  the  bottom  of  the  other,  the 
hooking  attachment  in  the  bottoms,  however,  not 
hindering  standing  each  weight  upright.  The 
set  consists  of  a  10,  20,  50,  100,  200,  500,  and  1000 
gram  weight,  with  duplicates  of  the  20  and  the 
200-gram  pieces.  Each  weight  fits  readily  into  an 
apartment  in  a  neatly  japanned  cast-metal  holder. 

Set  complete  with  holder . 


.95 


2.76 


No.  16-460 


16—452  INTERHOOKING  LABORATORY  WEIGHTS. 

Set  complete  as  above  but  without  holder  .  .  .  2.25 


16—453  CAST  METAL  HOLDER  with  separate  compartment  for  each  weight  listed 

above  .  . $0.66 


16-460  SLOTTED  METRIC  WEIGHTS,  accurately  adjusted.  Set  of  1-500,  5-100, 

1-50,  2-20,  and  1-10  gram  weights  mounted  on  japanned  holder .  1.70 


No.  16-460 


16-477  SLOTTED  METRIC  WEIGHTS  and 
WEIGHT  HANGER  for  use  in  me¬ 
chanical  powers  experiments  where  large 
capacity  weights  are  not  needed.  Con¬ 
sists  of  a  nickel-plated  brass  hanger  ac¬ 
curately  adjusted  to  50  grams  weight,  and 
a  set  of  weights  same  quality  and  as 
listed  in  No.  16-460—1-500,  5-100,  1-50, 

2-20,  and  1-10  gram  weights. 

Set  complete  with  hanger .  2.20 

16-478  SLOTTED  METRIC  WEIGHTS,  separate 
weights  same  quality  as  listed  above. 

a  b  c  d  e 

Size,  grams  .  .  10  20  50  100  500 

Each .  $0.18  .22  .28  .35  .48 


No.  16-477 


16-479  WEIGHT  HANGER,  accurately  adjusted  to  weigh  50  grams.  Nickel-plated.  Same  as  used  in 
No.  16-477  . 


$0.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


63 


ADJUSTED  METRIC  CAST  IRON  WEIGHTS 

These  weights  are  made  from  carefully-designed  patterns,  provided  with  groove  and  raised  ring  which  enables 
them  to  be  readily  piled  on  top  of  one  another  without  danger  of  slipping  and  producing  confusion  in  the  lecture 
room  or  laboratory. 

The  slot  in  each  is  made  slightly  narrower  than  the  diameter  of  the  hole  in  the  center,  enabling  the  weight  to 
be  easily  put  on  and  taken  off  from  the  Pratt  Institute  Weight  Hanger  listed  below,  and  at  the  same  time,  preventing- 
the  weights  from  accidentally  falling  from  the  hanger.  See  above  cut. 

These  weights,  being  made  of  the  finest  quality  of  castings,  carefully  adjusted,  may  be  depended  upon  for  care¬ 
ful  work. 


16-485  .  a  b  c  d 

Size,  kilos .  H  1  2  5 

Each  . $0.48  .57  .75  1.60 


16—487  WEIGHT  HANGER,  Pratt  Institute  design. 

All  of  our  hangers  in  this  group  are  made  with  the  upper  portion  of  the  rod  cut  away  to  fit  the  slot 
in  the  weight,  while  the  main  part  of  the  rod  is  the  same  size  as  the  hole  in  the  center  of  the  weight. 
This  insures  the  weights  being  held  securely  in  position,  making  it  impossible  for  them  to  acci¬ 
dentally  fall  off,  and  at  the  same  time  rendering  it  easy  to  put  them  on  and  take  them  from  the 
hanger  without  removing  the  hook  from  its  support.  This  feature  adds  materially  to  the  ease  of 
their  use  in  the  laboratory  and  is  indispensable  where  large  laboratory  divisions  are  a  necessity. 

Hanger  accurately  adjusted  to  weigh  500  grams . 

16-489  SLOTTED  METRIC  WEIGHTS  WITH  WEIGHT  HANGER.  Set  consists  of  one  each  weights 
listed  under  No.  16-486  and  No.  16-487  Weight  Hanger . 


$0.90' 

4.15- 


UNADJUSTED  CAST  IRON  WEIGHTS 


These  weights  are  designed  for  Mechanical  Powers  experiments  in  Applied  Physics.  While  not  adjusted  to 
exact  weights,  being  cast  uniformly  from  carefully  adjusted  patterns,  they  are  sufficiently  accurate  for  all  the  uses 
for  which  they  are  designed. 

As  may  be  noted  from  the  illustration,  there  are  three  series.  The  slots  in  all  the  weights  are  of  uniform  size. 
The  rods  on  all  the  hangers  are  of  the  same  size,  the  only  difference  being  in  the  size  of  the  supporting  disc  and  in 
the  length  of  the  supporting  rod. 

We  recommend  Hanger  d  for  Weights  a,  b  and  c;  Hanger  g  for  Weights  e  and  f,  and  Hanger  j  for  Weights  b. 
and  i.  (See  tabulation  below.) 


SERIES  1 

Weights  Hanger 
16-500  ...  a  be  d 

Size,  pounds  H  HI 

Each  ....  $0.11  .14  .18  .45 


SERIES  2 


Weights 
e  f 

2  5 

$0.27  .68 


Hanger 

g 


SERIES  3 


Weights 
h  i 

10  20 

$1.07  1.74 


Hanger 

j 


.90 


.62 


64 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


TIME  —  INDICATORS  —  SPEED 

CLOCKS,  PENDULUMS,  METRONOMES,  ETC.;  SPEEDOMETERS 

7-10  LABORATORY  CLOCK  for  general  use  as  an  accurate  time¬ 
keeper  and  for  beating  seconds. 

This  clock  has  an  eight-day,  standard  movement,  weight  driven, 
and  we  guarantee  its  reliability  as  an  accurate  time-keeper. 

The  lens-shaped  bob  is  of  polished  brass  and  the  pendulum 
is  full  seconds  length,  the  center  of  oscillation  being  readily 
adjusted  by  means  of  a  thumb-screw.  The  dial,  designed 
especially  for  laboratory  usage,  is  not  confused  by  the  usual  large 
hour  numerals,  for  since  in  laboratory  practise  seconds  beats 
are  essential,  the  seconds  divisions  are  the  most  prominent. 

Thus  in  our  dial,  the  hour  and  minute  divisions  with  their  hands 
are  small,  while  the  seconds  divisions  are  large  and  the  seconds 
hand  is  long.  All  three,  however,  are  sufficient  in  size  to  be 
readily  seen  from  any  part  of  the  laboratory. 

The  mercury  well  is  of  improved  design,  exposing  a  thin  strip  of 
mercury  adjusted  by  means  of  an  easily  accessible  knurled 
thumb-screw.  The  graduated  arc  affords  an  excellent,  simple 
device  for  leveling,  when  setting  up  the  clock  in  the  laboratory. 

The  case  of  our  clock  is  of  polished  mahogany,  designed  practically 
dust-proof.  It  is,  in  appearance,  equal  to  the  excellent  quality 
of  the  movements  which  it  contains.  It  is  provided  with  bind¬ 
ing  posts  for  electrical  connections  for  attaching  battery  and 
sounder  .  . $64.00 

17-15  MAGNETIC  CLOCK  CONTACT  for  attachment  to  any  labora¬ 
tory  clock,  making  an  adjustable  positive  contact  that  cannot 
get  out  of  order. 

The  design  of  a  magnetic  clock  contact  was  first  suggested  to  avoid 
the  disagreeable  features  accompanying  a  mercury  contact. 

The  contact  is  positive  and  the  make-and-break  instantaneous. 

It  is  readily  attached  to  any  seconds  pendulum,  or  any  make 
laboratory  clock  with  swinging  pendulum.  Complete,  ready 
for  attachment . 12.00 

17-26  INTERVAL  TIMER.  This  is  a  well-made,  handsomely  nickel- 
plated  and  reliable  interval  timer  especially  valuable  in  all 
experiments  in  which  action  for  a  definite  length  of  time  is 
necessary.  The  alarm  may  be  set  to  ring  at  the  expiration  of 
any  interval  from  one-quarter  of  a  minute  up  to  two  hours. 
Complete  with  directions .  2.46 


No.  17-10 

17-40  DISSECTED  CLOCK,  for  student’s  use  in  the  study 
of  weight-driven  clocks.  All  parts  are  mounted  on 
card  numbered  or  lettered  for  easy  reference.  All 
parts  are  substantially  built  and  accurately  fitted  and 
no  tools  are  necessary  in  assembling.  Being  of  sim¬ 
ple  construction,  no  mechanical  skill  is  needed  to  as¬ 
semble,  —  directions  furnished  with  each  clock  being 
full  and  simple.  Assembled,  the  clock  will  keep  good 
time. 

This  clock  is  highly  recommended  for  its  educational 
value  in  making  clear  the  complexity  of  parts  of  an 
expensive  time-keeper.  It  has  the  further  value  of 
increasing  the  interest  of  the  student.  Complete, 
with  full  directions,  in  a  neat  box . $2.46 


No.  17-40 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


65 


No.  17-60 


No.  17-60 


No.  17-75 


17-60  FULL-SWEEP  SECONDS  PENDULUM  for  beating  seconds  in  laboratories  where  the  more  expensive 
laboratory  clock  *s  not  available. 

This  pendulum  consists  of  a  full-sweep  seconds  pendulum  with  metal  bob,  cast  lens-shape  to  over¬ 
come  air  resistance,  and  suspended  on  ground  and  polished  steel  edges  in  a  special  stirrup.  It  is 
mounted  on  polished  hardwood  board  with  an  adjustable  mercury  well  designed  to  expose  a  thin 
strip  of  mercury  sufficient  to  cause  a  positive  contact.  The  mercury  is  adjusted  by  means  of  a 
screw.  Further  adjustment  is  possible  by  the  adjustable  contact  tip.  Binding  posts  are  con¬ 


veniently  placed  for  connection  of  battery  and  sounder . $  6.90 

17-66  FLASH  SECONDS  PENDULUM,  after  Turner  and  Hersey  (Exp.  S010) .  1.30 


17-60  ZINC  AND  IRON  COMPENSATING  PENDULUM,  illustrating  employment  of  metals  having 
different  coefficients  of  expansion  in  keeping  the  distance  between  the  center  of  suspension  and 
the  center  of  oscillation  constant.  Consists  of  alternate  rods  of  zinc  and  iron,  so  attached  that  the 
expansion  of  one  is  compensated  by  the  expansion  of  the  other.  Mounted  on  neatly  finished  base  .  12.36 

17-76  COMPENSATING  MERCURY  PENDULUM,  an  accurately  constructed,  handsomely  finished,  full- 
length  seconds  pendulum,  compensated  by  the  expansion  of  mercury. 

This  design,  a  modification  of  the  Graham’s  mercury  pendulum,  consists  of  a  steel  rod  as  in  a  simple 
seconds  pendulum,  but  in  place  of  the  disc  bob  are  suspended  two  glass  mercury  wells  in  suitable 
holders.  All  adjustments  are  provided.  Simply  operated  and  effectively  working.  The  apparatus 
is  handsomely  finished  throughout  and  the  quality  of  workmanship  is  of  the  finest. 

Complete  as  illustrated,  with  stirrup,  but  without  mercury .  6.76 


66 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


17-90  CLOCK  DEMONSTRATION  BALANCE  WHEEL,  —  two  compound  bars,  electrically  welded  and 
mounted  in  connection  with  a  spring,  substantial  base,  pivot  bearing,  as  indicated  in  the  accom¬ 
panying  illustration,  showing  clearly  the  principle  of  the  self-regulating  balance  wheel  in  watch 

and  clock  movements .  . $4.25 

17-120  METRONOME  for  time-marking  in  laboratory  experiments  in  the  study  of  Falling  Body,  Pen¬ 
dulum,  etc.  This  instrument  has  a  graduated  scale  and  a  marker  operated  by  spring-driven  clock¬ 
work  enclosed  in  polished  mahogany  case .  3.60 

17-125  METRONOME  WITH  BELL.  This  is  the  same  quality  Metronome  as  above,  but  has  the  additional 
feature  of  a  bell  attachment  which  can  be  regulated  to  sound  every  beat,  every  second,  third  or 

fourth  beat  as  desired .  6.36 

17-160  STOP  WATCH,  an  indispensable  accessory  to  the  equipment  of  any  well-equipped  laboratory. 

This  watch  is  of  excellent  quality,  stem  wound,  lever  movement,  beating  one-fifth  seconds,  neatly 

polished  nickel  case  with  stop . .  .  .  . .  7.10 

17-166  STOP  CLOCK,  with  5-inch  dial  and  with  seconds  hand.  In  highly-polished  mahogany  case.  De¬ 
signed  to  be  hung  on  the  wall  or  placed  on  a  table.  This  clock  is  an  accurate  time  keeper,  having 
the  distinctive  feature  of  being  an  inexpensive  stop  clock  with  qualities  that  would  warrant  its 
adoption  in  class-room  demonstrations .  9.80 


No.  17-200 


17-200  UNIVERSAL  SUN  DIAL.  In  our  Sun  Dial,  which  may  be  adapted  to  any  latitude,  we  offer  an  in¬ 
strument  scientific  in  design  and  capable  of  accurate  work.  It  is  12  inches  square,  substantially 
constructed  of  metal  and  can  be  continuously  exposed  in  any  climate  without  injury.  By  an 
ingenious  arrangement,  not  illustrated,  a  correct  setting  for  any  latitude  can  easily  be  obtained. 

We  supply  with  each  instrument  a  printed  form  on  which  a  correction  curve  for  any  locality  can 
readily  be  plotted  from  full  and  explicit  directions  furnished  with  each  instrument. 

Each  instrument  is  durably  finished  with  a  protective  coating,  the  figures  and  lines  showing  in  colors 
against  the  black  finish  on  the  casting. 

Universal  Sun  Dial,  complete  with  directions  for  correct  setting  for  any  latitude .  7.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


67 


No.  17-300 


No.  17-305 


No.  17-326 


[No.  17-310 


17-300  IMPROVED  SPEED  COUNTER  for  measuring  speed  of  rotation  of  shafts  in  efficiency  experi¬ 
ments,  etc.  The  indicating  dial  is  graduated  into  one  hundred  parts  and  graduations  show  every 
revolution  and  with  two  rows  of  figures  which  read  both  right  and  left . ' . $1.10 

17—306  SELF-REGISTERING  SPEED  COUNTER.  Registers  up  to  9,999  revolutions  on  low  or  high 


speeds  up  to  5000  R.  P.  M.  Registers  in  either  direction.  When  shaft  turns  one  way  the  counter 
adds,  the  other  way  it  subtracts.  Complete  with  one  pointed  and  one  flat  insulating  tip  ...  .  3.40 

17-310  SELF-REGISTERING  SPEED  COUNTER.  Registers  in  either  direction  up  to  99,999  revolutions  1.50 

17-326  SELF-REGISTERING  HAND  COUNTER.  Operated  by  slight  hand  pressure  upon  small  lever 

shown  in  illustration.  Complete  with  socket  plate .  2.00 


MATHEMATICAL  MODELS 


4  li  9^0  & 

13  14  15  16  17  18  19  20  21 


22  23  24  25  26  27  28  29  30 


38 


L^Z. 


39  40  41  42  43  44 

No.  18-10 


18-10  GEOMETRICAL  WOODEN  FORMS,  consisting  of  twenty-four  solids,  seventeen  surfaces,  and 
three  angles,  the  latter  being  represented  by  bent  wires.  Solids  are  accurately  turned  from  well- 
seasoned  hard  wood,  surfaces  cut  with  accurate  steel  dies  from  stiff,  hard,  light-colored  board. 
Complete  in  strong  wooden  box,  with  table  of  contents  pasted  on  the  under  side  of  the  cover  .  .  .  $2.95 


68 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  18-20  No.  18-50 


18-20^  CONE,  SPHERE,  and  CYLINDER  for  ocular  demonstration  of  the  relation  between  the  contents  of 
cone,  sphere,  and  cylinder.  The  cone  and  cylinder  are  3  inches  deep  by  3  inches  in  diameter.  Actual 
demonstration  shows  that  the  cone,  three  times  filled  with  water,  fills  the  cylinder,  and  that  the 
cylinder  filled  with  water  and  sphere  submerged,  enough  water  will  remain  in  the  cylinder  to  fill  the 
cone,  thus  showing  that  their  contents  are  as  the  ratio  1:2:3 . Per  Set  $1.10 

18-30  DISSECTIBLE  CONE  for  illustrating  conic  sections,  circle,  ellipse,  parabola,  and  hyperbola.  This 
cone  is  made  of  different  kinds  of  hard  wood,  highly  polished  on  the  surface,  each  section  held  by 
large-  pins.  Being  of  ample  proportions,  sections  are  of  convenient  demonstrating  sizes .  3.35 

18-40  TRIANGLE  DEMONSTRATION  APPARATUS  for  demonstrating  mechanically  that  the  area  of  a 

triangle  is  equal  to  its  base  multiplied  by  one-half  its  altitude. 

The  apparatus  consists  of  two  triangles  so  hinged  that  by  simply  swinging  certain  parts  on  their 

hinges,  the  triangles  resolve  themselves  into  two  rectangles  12  inches  long  by  3  inches  high  .  .  .  1.45 

18-60  CIRCLE  AREA  DEMONSTRATION  APPARATUS  for  demonstrating  mechanically  that  the  area 
of  a  circle  is  equal  to  the  radius  multiplied  by  one-half  the  circumference.  The  apparatus  consists 
of  a  large  number  of  sectors  attached  at  their  bases  by  a  pliable  band  connecting  them  by  hinges. 

This  band  is  in  two  parts,  so  that  the  circle  made  of  sectors  may  be  separated  into  two  semi-circles. 

When  these  two  semi-circles  are  straightened  out,  two  toothed  forms  result.  By  inserting  the  teeth 
of  one  form  between  the  teeth  of  the  other  a  rectangle  is  formed.  The  base  of  this  rectangle,  then, 
is  a  semi-circumference  and  its  height,  the  radius  of  the  circle.  The  diameter  of  disc  is  8  inches  .  2.10 

18-52  BRASS  DISC,  8  centimeters  diameter  with  radius  indicated,  after  Millikan,  Gale  and  Bishop  (Exp. 

1) . 27 

18-66  HOLLOW  BRASS  CYLINDER,  with  glass  cover,  after  Millikan,  Gale  and  Bishop  (Exp.  2)  .  .  .  .  .65 

18-60  CUBE  ROOT  BLOCKS  for  illustrating  in  a  simple  manner  the  underlying  principles  of  cube  root 
extraction.  The  apparatus  consists  of  an  accurately  dissectible  wooden  cube,  the  size  of  the  inner 
cube  being  3  inches  on  an  edge  and  the  assembled  cube  being  4  inches .  2.00 


MODELS  OF  CRYSTALS 


No.  18-126 


18-126  CRYSTAL  MODELS  OF  SOLID  GLASS,  a  set  consisting  of  six  models,  representing  the  six  basic 

geometrical  forms.  In  neat  cardboard  case . $4.76 

18-130  CRYSTAL  MODELS  OF  SOLID  GLASS,  a  set  of  twenty  different  forms,  surfaces  ground  and  pol¬ 
ished,  axes  3  to  6  centimeters  in  length.  Enclosed  in  case . Duty  Free  8.00 

18-200  CRYSTAL  MODELS  OF  WOOD,  consisting  of  thirteen  different  forms,  representing  the  most  com¬ 
mon  crystal  formations.  In  cardboard  box .  .  .  2.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


69 


DRAWING  INSTRUMENTS 

In  listing  our  line  of  drawing  instruments,  we  have  in  mind  the  elementary  requirements  of 
such  a  class  of  goods,  yet  we  believe  that  fewer  instruments,  rather  than  cheaper  grade,  are  ad¬ 
visable  if  the  school’s  appropriations  will  not  warrant  the  expenditure  for  such  instruments. 

The  line  of  instruments  which  we  list  are  made  of  hard-pressed  German  Silver,  and  finished 
steel.  They  have  received  all  the  improvements  of  fine  tools  and  will  be  found  capable  of  very 
exact  work. 


No.  19-10 


No.  19-12 


19-10  DRAWING  INSTRUMENTS,  good  quality  hard-pressed  German  silver  and  polished  steel,  contain¬ 
ing  the  following  instruments,  in  a  neat  leather  case,  lined  with  velvet: 

Ruling  pen,  5  inches,  with  patented  spring  back  lever. 

Compass,  534  inches,  with  fixed  needle  point,  pen,  and  pencil  point. 

Plain  dividers,  534  inches. 

Metal  protractor,  334  inches. 

Box  of  leads.  Complete  set  $1.50 

19-12  DRAWING  INSTRUMENTS,  extra  quality  hard-pressed  German  silver  and  polished  steel.  Set  con¬ 
taining  the  following  instruments  in  a  neat  morocco  pocket  case  lined  with  velvet: 

Ruling  pen,  534  inches,  with  patented  spring  back  lever. 

Compass,  6  inches,  with  fixed  needle  point,  pen,  pencil  point,  and  lengthening'Jbar. 

Steel  divider  point. 

Box  of  leads.  .  Complete  set  2.65 


No.  19-14 


19-14  DRAWING  INSTRUMENTS,  extra  quality  hard-pressed  German  silver  and  polished  steel.  Set  con¬ 
taining  the  following  instruments,  in  morocco  pocket  case  lined  with  silk  velvet: 

Ruling  pen,  5  inches,  with  patented  spring  steel  back. 

Plain  divider,  6  inches. 

Compass,  6  inches,  with  fixed  needle  point,  pen,  pencil  point  and  lengthening  bar. 

Steel  spring  bow  pencil,  3 34  inches. 

Steel  spring  bow  pen,  3 34  inches. 

Steel  spring  bow  divider,  334  inches. 

Box  of  leads. 


Complete  set  4.80 


70 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


19-20 

19-23 


19-25 

19-30 

19-32 

19-34 


19-40 

19-41 

19-42 

19-43 

19-50 


No.  19-23 


No.  19-34 


SCHOOL  COMPASS,  as  illustrated  in  set  No.  19-10,  with  fixed  needle  point  and  pencil  point  .  .  . 
UNIVERSAL  PENCIL  COMPASS  for  student’s  use  in  diagram  work  in  laboratory.  These  pencil 
compasses  are  inexpensive,  yet  strong  and  serviceable.  Capable  of  drawing  circles  up  to  12  inches 
in  diameter. 

Complete  as  illustrated,  with  pencil . . Per  Dozen 

STEEL  SPRING  BOW  DIVIDER,  inches,  as  included  in  set  No.  19-14 . 

PARALLEL  RULE,  best  quality,  made  of  clear  ebony  with  brass  mountings.  Length  12  inches  .  . 

T-SQUARE,  cherry  wood,  24  inches  long,  with  fixed  cross  head . 

AMBRO  UNIVERSAL  SET  SQUARE.  This  square,  imported  by  us,  has  many  features  which  can 
only  be  realized  by  use.  Designed  to  secure  the  same  utility  as  a  number  of  instruments,  it  has  ad¬ 
vantages  over  each,  in  that  it  can  be  instantly  adjusted  to  perform  their  various  duties.  It  is  an 
accurate  protractor,  graduated  to  read  from  0  to  90  degrees  in  two  directions;  it  is  an  accurate  try 
square;  it  is  a  right  angle  triangle;  it  is  a  straight  edge,  etc.,  etc. 

It  is  substantially  constructed  and  its  accuracy  is  unexcelled.  Its  universal  adaptation  to  uses  of  many 
instruments  at  a  cost  far  below  that  of  these  instruments  is  a  feature  to  which  we  desire  to  call 

particular  attention  .  .  : . . . 

PEARWOOD  TRIANGLE,  framed,  extra  quality,  30  degrees.  Size  10  inches . 

- ,  same  as  above,  but  45  degrees.  Size  8  inches . 

TRANSPARENT  AMBRO  TRIANGLE,  30  and  60  degrees.  Size  10  inches . 

- ,  same  as  above,  but  45  degrees.  Size  8  inches . 

DRAWING  BOARDS  of  clear  grained  pine  wood,  having  two  drawing  surfaces,  with  side  ledges. 


a  b  c 

Size .  16  X  22  20  X  24M  2 3  X  31  inches. 

Each .  $1.05  $1.60  $2.15 


$1.15 


1.50 

.72 

1.00 

.40 


1.75 

.26 

.28 

.77 

.77 


Nos.  19-67  to  19-68 


19-65  CROSS-SECTION  PAPER,  %  inch  divisions,  printed  on  heavy  bond  paper  17  X  22  inches. 

Sheet  $0.06.  Doz.  $0.68 

19-67  CROSS-SECTION  PAPER.  One  millimeter  divisions  with  heavy  centimeter  rulings  15  X  20  centi¬ 
meters,  on  heavy  bond  paper  8J^  X  10j^  inches.  This  is  our  National  Physics  Note-Book  Cross- 

Section  Sheet  with  holes  punched  for  use  in  our  Binders . Per  100  Sheets  .60 

19-68  CROSS-SECTION  PAPER,  same  ruling  as  No.  19-67,  but  printed  on  drawing  paper  22  X  27  cen¬ 
timeters  . Per  100  Sheets  1.80 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


7i 


No.  19-75 

19-70  BLACKBOARD  DIVIDER  AND  COMPASS.  Superior  quality,  substantially  constructed  and 
handsomely  finished. 

Length  16  inches . $0.60 

19-76  EXTRA  LARGE  BLACKBOARD  DRAWING  INSTRUMENTS.  Essential  where  accurately  con¬ 
structed  diagrams  are  required  of  either  teacher  or  pupil. 

These  instruments,  imported  by  us,  must  not  be  confused  with  the  ordinary  quality  on  the  market. 

The  set  offered  under  this  number  is  accurately  and  substantially  constructed,  each  being  provided 
with  conveniently  situated  handle.  The  set  is  made  from  the  best  close-grained,  well-seasoned 
wood,  polished  and  oil  finished.  The  ruler  is  a  full  meter,  graduated  the  full  length  into  clear,  dis¬ 
tinct,  black  filled  divisions.  The  triangle,  50  centimeters  long,  has  angles  of  45  and  90  degrees. 

The  protractor,  40  centimeters  in  diameter,  has  two  scales,  the  linear  and  angular,  the  latter  reading 


in  two  directions,  divisions  and  figures  filled  black . Set  of  Three  6.25 

19-77  - ,  similar  to  above  but  ordinary  grade .  4.50 


19-100  GRAPH  CHART,  graph  36  X  36  inches, 
lithographed  on  blackboard  canvas 
3X4  feet,  mounted  on  plain  roller. 

Each  square  measures  exactly  one 
inch.  The  center  lines  are  extra  heavy 
and  are  accurately  squared. 

This  chart  simplifies  the  reading  of 
co-ordinates  and  other  mathematical 
principles,  plotting  of  geometrical 
figures,  projection  of  planes,  curves, 
etc.,  for  showing  progress  of  experi¬ 
ments  in  Physics,  and  is  practically 
indispensable  for  graphic  representa¬ 
tion  of  temperature,  rainfall  and 
humidity  in  Physical  Geography.  It 
may  be  considered  a  necessity  in  high 
school  work . $3.25 


J 


No.  19-100 


72 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MECHANICS 

PROPERTIES  OF  MATTER 


No.  20-10 


No.  20-20 


No.  20-25 


20-10  POROSITY  DEMONSTRATION  APPARATUS  for  illustrating  the  porosity  of  wood.  Apparatus 
consists  of  an  oak  wood  funnel,  a  conveniently  sized  bell  glass  and  glass  dish  as  illustrated. 

In  use,  the  apparatus  is  placed  grouped  as  illustrated  on  the  plate  of  an  air  pump.  Mercury  is  placed 
in  the  wood  funnel.  After  a  few  strokes  of  the  lever,  the  mercury  will  begin  to  run  through  the 
pores  of  the  wood  into  the  glass.  Complete  as  illustrated . $1.70 

20-11  WOOD  FUNNEL,  as  used  in  above .  *86 


20-12  BELL  GLASS,  as  used  in  above .  .86 

20-13  GLASS  DISH,  as  used  in  above . 10 

20-20  VISCOSITY  APPARATUS  for  determining  the  viscosity  coefficient  of  a  liquid.  Apparatus  consists  of 
a  capillary  tube  with  bulb  so  that;-£he  time  of  outflow  is  at  least  100  seconds.  The  liquid  flows 
under  its  own  pressure  to  the  capittlry.  An  accurately  known  quantity  is  introduced  into  the 
wider  tube  and  then  sucked  up  the  other  tube  until  the  liquid  has  risen  above  the  bulb.  The 
time  occupied  by  the  liquid  flowing  from  this  height  to  a  point  below  the  bulb  is  noted  and  co¬ 
efficient  determined .  1.60 


20-25  JENKINS’  SPECIFIC  GRAVITY  APPARATUS.  This  apparatus  employs,  in  principle,  the  ef¬ 
fusion  test  of  Bunsen  which  is  based  on  the  fact  that  the  specific  gravities  of  two  gases  are  in¬ 
versely  proportional  to  the  squares  of  the  speeds  with  which  they  escape  through  a  minute  open¬ 
ing.  It  is  used  by  the  Gas  Inspectors  of  Massachusetts  and  New  York  for  specific  gravity  de¬ 
terminations  and  will  be  found  sufficiently  accurate  for  all  practical  purposes.  It  will  be  found 
fully  as  accurate  as  the  Schilling’s  Specific  Gravity  Apparatus  so  frequently  found  in  use,  and  the 
cost  is  considerably  less. 

The  advantages  of  the  Jenkins’  Specific  Gravity  Apparatus  are,  —  its  portability,  its  low  cost,  its 
rapidity  and  accuracy. 

Complete  directions  furnished  with  each  outfit  sold.  Price,  complete  with  stand . 12.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


73 


20-90 


20-96 


20-100 


20-110 


20-116 


20-117 


20  120 


No.  20-90 


LEAD  COHESION  DISCS  for  illustrating  molecular  cohesion  between  metals.  Apparatus  con¬ 
sists  of  two  hemispheres  of  lead  with  faces  carefully  ground  smooth. 

When  the  two  surfaces  are  pressed  tightly  together,  the  cohesion  between  the  lead  molecules  offers  a 

resistance  to  separation .  $0.38 

GLASS  COHESION  DISCS  for  illustrating  molecular  cohesion  between  two  glass  plates.  Apparatus 
consists  of  two  all-glass  hemispheres  with  carefully  ground  faces. 

When  the  two  faces  are  pressed  tightly  together,  the  cohesion  between  the  glass  molecules  offers  a 

resistance  to  separation .  .66 


FILM  DEMONSTRATION  APPARATUS  for  illustrating  characteristics  of  films  demonstrating 
Surface  Tension  and  Cohesion. 

The  apparatus  consists  of  three  wire  frames  of  different  forms  with  pipe  for  blowing  spherical  films. 

Striking  results  are  possible  from  proper  use  of  these  frames.  Tendency  of  all  films  to  attain  a  cir¬ 
cular  form  is  quite  noticeable . Per  Set  as  Illustrated  .90 


No.  20-110 


No.  20-116 


PRINCE  RUPERT  DROPS  for  illustrating  the  stress  existing  between  the  inside  and  outside  of  a 
glass  when  it  is  allowed  to  cool  suddenly.  These  drops  consist  of  drops  of  glass  which  had  their 
surfaces  cooled  suddenly  so  that  they  became  rigid,  before  the  inner  surface  had  had  time  to  cool. 

There  is  considerable  stress,  therefore,  between  the  outside  and  the  inside,  but  the  stress  being 
distributed  over  the  surface,  a  state  of  equilibrium  exists  which  is  only  disturbed  when  a  small 
portion  is  broken,  when  the  drop  will  explode  into  very  small  pieces.  In  use,  therefore,  the  drop 
should  be  covered  with  a  piece  of  paper  so  that  when  the  small  tail  is  broken  off  no  one  will  be 
exposed  to  the  flying  fragments . Per  Dozen  $0.26 

BOLOGNA  PHIALS.  These  phials  are  made  in  a  similar  manner  to  the  Prince  Rupert  Drops  and 
illustrate  the  stress  existing  by  allowing  small  pieces  of  flint  to  move  about  inside  the  flask,  thus 
causing  small  scratches  which  result  in  the  bottom  flying  to  pieces.  This  is  a  spectacular  experi¬ 
ment,  as  only  a  very  slight  scratch  will  cause  the  bottom  to  fly  out . Per  Ten  1.50 

ADHESION  DISC  for  illustrating  adhesion  between  glass  and  a  liquid.  Apparatus  consists  of  a 
circular  glass  plate,  3  inches  in  diameter,  having  at  its  center  a  polished  wood  cone  at  the  apex  of 
which  is  fastened  a  fine  thread  for  attachment  to  a  balance  arm  when  experimenting  .  .  .  Each  .30 

FRICTION  OF  WATER  APPARATUS  for  showing  the  increase  of  friction  caused  by  a  film  of  water 
between  metal  surfaces.  (Hall  No.  XXVH) . • 


2.26 


74 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  20-126 


20-126  GLASS  PLATES  FOR  ILLUSTRATING  CAPILLARITY.  Consists  of  2  plates  of  glass,  which  may 
be  placed  in  a  shallow  dish  of  water  at  any  desired  angle,  when  a  curve  will  result  somewhat  as 


illustrated  .  Per  Pair  $0.26 

4 

20-126  GLASS  PLATE  SEPARATOR  for  holding  2  glass  plates,  as  No.  20-125,  at  any  desired  angle  in  a 

dish  of  water.  Consists  of  a  small  wedge  with  detents  for  holding  to  tops  of  the  plates .  .60 


20-130  TAPERING  CAPILLARY  TUBES  for  demonstrating  capillarity  in  tubes.  Consists  of  a  tapering 
glass  tube  4  inches  long. 

This  is  a  very  excellent,  inexpensive  piece  of  apparatus  for  demonstrating  capillarity  in  tubes  of 

different  diameters .  .  $0.36 

20-132  CAPILLARY  TUBES,  set  of  4  tubes  of  different  internal  diameters,  4  inches  in  length  .  .  .  Per  Set  .30 

20-134  CAPILLARY  TUBES  ON  SUPPORT,  consisting  of  a  set  of  four  tubes  of  different  diameters,  mounted 


on  support,  for  placing  over  top  of  a  small  jar .  .40 

20-136  SMALL  JAR,  for  use  with  No.  20-134  Capillary  Tubes .  J.0 


20-137  CAPILLARY  TUBES,  set  of  eight  tubes  of  different  internal  diameters  for  illustrating  capillarity 

Per  Set  .46 

20-140  CAPILLARY  TUBES  AND  STAND,  consisting  of  eight  tubes  of  different  internal  diameters  mounted 
in  a  stand. 

The  stand  illustrated  is  a  valuable  adjunct  in  the  study  of  capillarity,  in  that  it  allows  of  view  of  a 


number  of  tubes  at  the  same  time,  also  affording  convenient  means  for  lantern  projection.  Fin¬ 
ished  in  japan  and  gun-metal  finish.  Stand  complete  with  eight  tubes  of  different  internal  diam¬ 
eters  .  1.16 

20-145  CAPILLARY  TUBES,  consisting  of  four  capillary  tubes  of  different  internal  diameters  connected  to 

a  water  reservoir.  For  illustration  see  No.  20-150  .  .76 

20-150  CAPILLARY  TUBES  AND  SUPPORT,  consisting  of  No.  20-145  Capillary  Tubes,  mounted  on  a  neat 
cast-iron  base.  Base  is  provided  wuth  lacquered  brass  clips  for  holding  glass  part  in  place.  Stand 
is  handsomely  finished  in  japan .  1.22 

20-156  CAPILLARY  U-TUBE,  consisting  of  glass  U-tube,  one  branch  of  which  is  a  small  capillary  tube 

with  white  backing .  .33 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


75 


20-160 


20-200 


20-215 


20-220 


22-130 

6-860 

31-266C 

20-222 


CAPILLARY  TUBES 
ON  STAND,  con- 
sisting  of  ten 
U-tubes,  one 
branch  of  each 
being  capillary, 
and  all  of  different 
internal  diameters, 
mounted  on 
support  with  scales 
for  noting  relative 
rise  of  liquid  in  the 
tubes . 


$6.15 


No.  20-160 


ft* 

w 


No.  20-200 


No.  20-215 


$3.70 


1.25 


No.  20-220 


ENDOSMOMETER  for  illustrating  the  phenomena  of  Endosmose 
and  Osmose. 

The  apparatus  consists  of  a  glass  vessel  the  lower  end  of  which  is 
covered  by  a  membrane,  the  upper  end  of  which  is  connected  to  a 
glass  tube  which  carries  a  scale.  This  vessel  is  supported  so  that 
the  membrane  is  held  under  solution  during  examination. 

All  parts  complete  as  illustrated . 

STUDENTS’  OSMOSIS  APPARATUS  for  qualitative  as  well  as 
quantitative  work  in  Osmosis. 

The  apparatus  consists  of  an  osmosis  tube  of  design  as  illustrated, 
held  adjustably  in  a  nickel-plated  clamp  which  may  be  clamped 
to  the  side  of  a  jar.  One  end  of  the  osmosis  tube  is  closed  by  a  thin 
porous  membrane  which  may  be  removed  and  replaced  from  time 
to  time  as  needed. 

Apparatus  complete  as  illustrated . 

OSMOSIS  APPARATUS  after  specifications  by  Thos.  B.  Freas  of  the  Department  of  Chemistry, 
Columbia  University,  for  illustrating  the  phenomenon  of  Osmotic  Pressure. 

This  ingenious  device  consists  of  an  S.  &  S.  diffusion  shell  attached  to  a  glass  chamber  which  ends 
above  in  a  heavy  wall  barometer  tube  5  feet  long.  Entering  this  chamber  is  another  tube  with 
a  funnel  end  and  stop-cock  through  which  the  solution  is  allowed  to  flow. 

For  ease  and  rapidity  of  illustration  this  apparatus  is  unexcelled  and  the  results  are  readily  notice¬ 
able  within  fifteen  minutes  from  the  start. 

Osmosis  Tube  with  diffusion  shell  only,  without  support  of  any  kind .  $3.90 

Articles  illustrated  in  addition  are: 

UNIVERSAL  STAND .  2.10 

UNIVERSAL  RIGHT-ANGLE  CLAMP .  1.05 

BATTERY  JAR,  6X8  inches . 40 

DIFFUSION  SHELL,  as  used  in  above  apparatus . Each  $0.40,  Per  Ten  4.00 


76 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


20-230 


20-235 


SCHIFF’S  SURFACE  TENSION  APPARATUS  for  the  study  of 
surface  tension  in  liquids. 

Consists  of  a  special  U-tube,  one  limb  of  which  has  large  bore,  the  other 
capillary  bore,  bent  at  the  top  at  right  angles  and  with  an  enlarge¬ 
ment  just  at  the  bend  to  prevent  stoppage  of  the  mouth  of  the  tube 
by  deposited  drops . 

HALL’S  SURFACE  TENSION  APPARATUS,  designed  by  Dr.  E.  H. 
Hall  of  Harvard  University  for  quantitative  measurement  of  surface 
tension.  This  apparatus  will  be  found  most  effective  for  determi¬ 
ning  the  surface  tension  of  any  liquid  not  acting  on  metal.  Com¬ 
plete  with  stand  as  illustrated . 


$1.10 


3.60 


No.  20-235 


20-235A  - ,  as  illustrated,  but  without  Stand . " . $2.96 

20-236  SHALLOW  FLINT  GLASS  DISH  for  above . 16 


No.  20-250 


No.  20-260 


No.  20-270 


20-250  INCOMPRESSIBILITY  OF  LIQUIDS  APPARATUS,  IMPROVED  DE- 
*  SIGN,  for  the  quantitative  observation  of  the  incompressibility  of  liquids. 

This  apparatus  consists  of  a  tube  with  indicating  capillary.  The  liquid  to 
be  observed  should  fill  the  short  arm  of  the  tube  and  should  rise  in  the  long 
arm  to  near  the  top  of  the  capillary.  If  mercury  is  poured  into  the  long 
arm,  the  liquid,  if  compressible,  will  indicate  the  amount,  if  any,  in  the 
capillary. 

Complete  as  illustrated,  mounted  on  our  No.  41-116  Boyle’s  Law  Stand  .  $4.26 

20-251  INCOMPRESSIBILITY  OF  LIQUIDS  TUBE,  only .  2.60 

20-260  IMPENETRABILITY  APPARATUS,  illustrating  the  fact  that  two  bodies 

cannot  occupy  the  same  space  at  the  same  time. 

This  apparatus  consists  of  a  frame  which  answers  the  double  purpose  of  sup¬ 
porting  the  bottle  and  plunger  and  of  a  clamp.  In  use,  the  bottle  is  filled 
with  the  liquid,  a  one-hole  rubber  stopper  placed  in  the  neck,  the  end  of  the 
plunger  placed  in  the  hole  and  the  bottle  clamped  firmly  in  place  by  means 
of  the  thumb  nuts.  If  the  plunger  is  now  thrust  into  the  bottle,  the  bottle 
will  burst,  demonstrating  that  two  objects  cannot  occupy  the  same  space 
at  the  same  time,  also,  that  a  liquid  is  incompressible. 

Complete,  with  three  bottles .  1.45 


20-270  INERTIA  APPARATUS  for  illustrative  demonstration  of  Inertia. 

The  apparatus  consistsjof  a  neatly  finished  base  on  which  is  mounted  a  nickel-plated  rod  with  con¬ 
cave  top.  A  metal  spring  fastened  to  the  side  of  the  base  affords  a  device  for  giving  the  card 
illustrated  a  sudden  blow  on  the  edge,  thus  knocking  the  card  from  under  the  small  ball,  show¬ 
ing  that  the  ball  does  not  change  its  position  except  as  gravity  causes  it  to  drop  into  concave 
top  when  its  prop  is  knockedjfrom  under. 

Complete  as  illustrated .  .85 


I 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


77 


CENTRIFUGAL  FORCE 


ROTATORS 


No.  21-10 


21-10  ZIEGLER  TWENTY-ONE  POUND  MECHANICAL  ROTATOR  OR  WHIRLING 
TABLE  with  universal  chuck  for  rotating  objects  to  which  it  is  desired  to  apply 
a  centrifugal  force. 


In  the  design  of  our  Rotator  we  have  observed  closely  all  the  scientific  requirements 
of  such  an  instrument.  It  is  made  of  cast  iron,  all  parts  neatly  japanned,  and 
may  be  used  in  either  a  vertical  or  horizontal  position.  In  design  of  our  patterns 
we  have  placed  the  metal  at  points  where  the  greatest  stability  may  be  secured. 
Furnished  with  each  rotator  are  the  various  attachments  for  fastening  the  acces¬ 
sories.  Thus  there  will  be  found  with  each  instrument  a  universal  chuck  for 
fastening  objects  with  a  spindle;  also  a  special  lock-nut  head  designed  for  fasten¬ 
ing  plates,  color  discs,  etc.,  and  for  attaching  the  string  of  such  accessories  as  the 
Disc,  Egg,  and  Chain. 

Important  features  of  this  instrument  are, — 

1.  Extreme  rigidity,  used  in  either  vertical  or  horizontal  position. 

2.  Large  Drive  Wheel,  facilitating  either  high  or  low  speed. 

3.  Handsome  and  durable  finish. 

Rotator  only,  without  accessories,  also  illustrated,  but  including  the  universal 

chuck  attachment .  . $6.95 


78 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


*  ) 


THE  UNIVERSAL  SPEED  AND  POWER 

ROTATOR 


Nos.  21-30  to  21-35 

Patent  Pending 


The  motor  rotator  is  desirable,  if  not  essential,  in  Physical  Laboratory  demonstration,  but  the  important  prob¬ 
lem  of  adequate  power  at  low  speed  has  not  before  been  solved,  two  hundred  revolutions  being  considered  the  low 
limit  at  which  reasonable  working  power  may  be  obtained. 

We  have,  by  the  friction  drive  method,  produced  a  Universal  Speed  and  Power  Rotator  which  runs  without 
unnecessary  friction  and  in  which  the  power  is  increased  as  the  speed  is  diminished,  a  feature  which  gives  to  it  a 
breadth  of  usefulness  not  ordinarily  looked  for  in  these  instruments. 

While  primarily  designed  for  all  of  the  usual  whirling  table  experiments,  it  serves  admirably  as  the  power  plant 
in  prony  break  tests  and  in  the  Mechanical  Equivalent  of  Heat  experiments  where  the  greatest  smoothness  as  well 
as  low  speed  and  great  power  are  required.  When  operated  at  high  speed  the  outfit  is  particularly  well  adapted  to 
the  energizing  of  gyroscopes  of  high  power. 

FEATURES 

UNIVERSAL  POSITION.  The  countershaft  housing,  being  designed  so  as  to  rotate  through  a  complete  circle, 
gives  any  desired  position  to  the  chuck  holder. 

A  SPEED  CONTROL  which  has  never  before  been  obtained  in  a  rotator,  from  0  to  5000  revolutions. 

A  METHOD  OF  REVERSING  which  is  as  simple  as  it  is  unique,  carrying  the  shaft  from  the  highest  speed  on 
one  side  gradually  down  to  0  and  gradually  up  to  the  desired  points  on  the  other  side,  all  without  jar  or  shock,  it 
being  accomplished  without  touching  a  switch  or  reversing  key. 

POWER.  Full  power  of  the  motor  when  the  countershaft  is  running  at  the  same  speed  as  the  motor  and  which 
increases  in  the  same  ratio  as  the  speed  diminishes,  giving  almost  unlimited  torque  at  very  low  speed.  The  crown¬ 
ing  of  the  drive  disc  so  as  to  insure  greater  contact  pressure  as  the  power  is  increased. 

SAFETY.  All  parts  enclosed  so  as  to  eliminate  all  danger  from  any  moving  portions  of  the  instrument. 

SPEED  COUNTER.  A  direct  connected  speed  counter  attached  to  the  countershaft,  giving  actual  number  of 
revolutions  of  the  effective  shaft.  The  counter  may  be  thrown  in  or  out  of  mesh  at  will. 

UNIVERSAL  CHUCK  SOCKET.  A  chuck  socket  which  readily  takes  all  of  the  whirling  table  attachments, 
requiring  no  wrench  for  adjustment. 

WEIGHT.  The  base  of  the  instrument,  a  solid  casting,  supported  by  shock-absorbing  points,  stands  firm  and 
rigid  on  the  lecture  table,  requiring  no  clamping. 


VOLTAGE  OF  CURRENT 

In  ordering,  specify  the  current  for  which  the  motor  is  desired: —  110  volts  D.  C.  or  110  volts,  60  cycles  A.  C. 
See  listing  below. 

21-30  Rotator  complete  with  Universal  Chuck,  for  110  volts  D.  C . $42.00 

21-36  Rotator  complete  with  Universal  Chuck,  for  110  volts  A.  C . 42.00 

.21-46  SPECIAL  DRIVE  PULLEY  for  round  belt.  This  drive  pulley  will  be  found  essential  when  using 
above  rotators  as  the  driving  mechanism  for  Mechanical  Equivalent  of  Heat  Apparatus  (see  page 
230)  or  other  apparatus.  It  is  designed  with  set  screw  to  attach  to  shaft  of  either  of  above  ro¬ 
tators  . $1.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


79 


ROTATOR  ACCESSORIES 


21-60  SPEED  INDICATOR  for  attachment  to  the  Whirling  Table  when  quantitative  results  are  desired. 

This  indicator  is  a  high-grade  instrument  especially  adapted  to  use  on  our  Rotator.  Illustration 

shows  method  of  attachment  to  the  Rotator . ; . $4.16 


21-60  SPRING  STEEL  DOUBLE  CENTRIFUGAL  HOOP  for  illustrating  the  tendency  of  a  semi-fluid  body, 
such  as  the  Earth,  to  assume  a  flattening  at  the  poles  when  rotating  rapidly. 

The  apparatus  consists  of  two  flexible  hoops  of  spring  steel  mounted  on  a  central  axis  for  attaching 

to  the  spindle  of  the  Rotator .  1.05 


21-80  FOUCAULT’S  PENDULUM  for  illustrating  conserva¬ 
tion  of  the  plane  of  oscillation. 

This  design  consists  of  a  carefully  finished  wooden 
disc  with  quadrants  clearly  marked,  the  under  side 
of  which  is  provided  with  an  accurately  centered 
spindle  for  attachment  to  rotator.  The  uprights 
support  a  pendulum,  the  point  of  suspension  being 
directly  over  center  of  the  disc. 

In  use,  the  pendulum  is  allowed  to  swing  in  the  plane 
of  the  apparatus  and  then  set  slowly  in  rotation. 

The  pendulum  will  maintain  the  course  of  its  plane 
of  vibration . $6.60 

21-100  CENTRIFUGAL  FORCE  APPARATUS,  consisting  of 
two  connected  balls  of  unequal  mass  mounted  on  a 
horizontal  rod  attached  to  a  frame  for  connection 
to  the  Rotator .  1.90 


No.  21-110 


21-110  CHAIN,  EGG  and  DISC  for  illustrating  the  tendency  of  a  body  to  rotate  about  its  shortest  diameter. 
Consists  of  a  Disc,  a  Chain  and  an  Egg-shaped  solid,  each  with  an  attached  cord  for  suspending  to 
the  head  of  the  Rotator . 


$0.88 


8o 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


No.  21-120 


No.  21-160 


No.  21-176 


21-120 


21-160 


21-162 

21-160 

21-176 


21-186 


21-190 


TYNDALL’S  INSULATED  HEAT  BY  FRICTION  ATTACHMENT  for  illustrating  heat  caused 
by  friction  on  a  brass  tube  while  rotating  rapidly. 

Apparatus  consists  of  a  cylinder  of  brass  carefully  insulated  from  the  brass  rod  with  which  it  is 
connected  to  the  rotator.  If  this  cylinder  is  filled  with  alcohol  and  friction  caused  during  rotation 
by  means  of  the  Friction  Vise,  it  will  be  noted  that  the  liquid  is  soon  boiling. 

Complete  as  described . $2.00 


CENTRIFUGAL  SEPARATOR  for  separating  by  centrifugal  force  solids  held  in  suspension  in  a 
liquid. 

The  apparatus  consists  of  a  spindle  with  cross  head.  To  the  forked  end  of  this  cross  head,  brass 
collars  are  held  in  cone  bearings.  In  these  collars  are  placed  the  centrifuge  tubes  with  their  alumi¬ 
num  shields. 

When  rotated  rapidly,  solids  held  in  suspension  in  a  liquid  contained  in  the  tubes  will  gather  at  the 

bottom .  2.46 

CENTRIFUGAL  TUBE,  after  Hall  (No.  XLI)  Figure  102  to  illustrate  centrifugal  action .  .68 

CENTRIFUGAL  DRYER  for  illustrating  the  principle  of  centrifugal  devices  as  used  in  laundries. 

For  illustration  see  page  77 .  3.90 

TWO-IN-ONE  GLASS  ROTATOR  GLOBE  for 


showing  effect  of  rotation  upon  solids  or  liquids 
of  unequal  weight.  This  apparatus  takes  the 
place  of  both  the  glass  globe  for  liquids  and  the 
open  shallow  dish  for  solids,  both  of  which  are 
required  for  complete  demonstrations. 

If  three  balls  of  same  size  but  unequal  weight,  or  if 
two  or  more  liquids  of  different  specific  gravities 
but  which  do  not  mix  (mercury  and  water)  are 
placed  within  the  globe  and  the  globe  rotated, 
interesting  and  instructive  phenomena  will  be 
noted.  This  globe  is  of  heavy  glass  and  carefully 
balanced  to  rotate  evenly . $2.85 

WATT’S  GOVERNOR  for  demonstrating  the  use¬ 
fulness  of  a  governor  on  an  engine. 

The  apparatus  consists  of  two  metal  balls  suspend¬ 
ed  to  two  arms  which  in  normal  position  hang 
downward,  but  pivoted  so  that  in  rotation  they 
are  free  to  rise  and  act  against  a  spring.  Made  of 
brass  throughout  and  finished  in  lacquer  and 
nickel .  3.96 

VALVE  REGULATOR,  to  be  used  in  conjunction 
with  above  Watt’s  Governor  in  demonstrating 
the  action  of  a  governor  in  regulating  the  flow  of 
steam  into  the  steam  chest  of  an  engine.  Fin¬ 
ished  in  bright  japan  with  different  parts  colored 
for  distinction  at  a  distance  from  the  lecture 
table .  3.40 


Nos.  21-186  and  21-190 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


81 


No.  21-210  No.  21-226 


21-210  LARGE  LECTURE  TABLE  COLOR  DISCS  for  quantitative  work  in  color  mixing  and  color  analysis. 

These  discs  are  of  heavy  cardboard  with  hole  for  attaching  to  spindle  of  Rotator.  Each  disc  is  slit 
that  two  or  more  colors  may  be  combined,  giving  a  disc  of  several  colors. 

Set  of  discs  of  seven  primary  colors,  one  each  of  black  and  white,  and  a  percentage  circular  pro¬ 
tractor  for  quantitative  work . $2.00 

21-226  COMBINATION  NEWTON’S  COLOR  DISC,  SIREN  DISC  and  SAVART’S  WHEEL  for  showing 
white  light  when  fixed  portions  of  primary  colors  are  rotated  rapidly,  and  for  demonstrating  prop¬ 
agation  of  sound  by  mechanical  disturbances  which  cause  vibration  in  the  surrounding  media. 

Consists  of  a  flat  disc  of  metal  with  part  of  the  face  covered  with  colored  segments  of  the  seven 
primary  colors  in  best  proportions  to  show  white  when  disc  is  rotated  rapidly.  Outside  this  col¬ 
ored  portion  there  are  drilled  five  rows  of  holes  on  concentric  circles,  four  of  which  are  evenly 
spaced  and  sound  the  tones  C,  E,  G,  and  C',  while  the  fifth  is  unevenly  spaced  and  sounds  a  harsh 
tone,  —  a  noise.  On  the  periphery  of  the  disc  are  cut  evenly  spaced  teeth . Each  .  1.60 


No.  21-240  No.  21-246 

t 

21-240  SAVART’S  TOOTHED  WHEEL  for  demonstrating  that  tones  are  produced  by  regular  impulses 
given  to  the  surrounding  media. 

Consists  of  four  brass  discs  on  the  periphery  of  which  are  cut  teeth,  which,  when  touched  by  a  card 
during  rotation,  will  sound  the  tones  of  C,  E,  G,  and  C'.  These  discs  are  held  fixed  to  a  spindle 
-  for  attaching  to  the  socket  of  the  Rotator.  Finished  in  nickel  throughout . $2.36 

21-242  - ,  similar  to  above,  but  with  only  one  wheel.  For  attachment  to  socket  of  the  Rotator  .  .  .  .48 

21-246  SAVART’S  TOOTHED  WHEEL,  mounted  on  stand  for  string  rotation.  Consists  of  a  heavy  metal 
casting  with  teeth  equally  spaced  on  the  periphery.  This  disc  is  mounted  on  axle  and  supported 
on  a  heavy  casting.  Durable  japan  and  black  oxidized  finish .  7.66 


82 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


21-266 


No.  21-267 


SIREN  DISC,  illustrating  sound  propagation  by  regular  im¬ 
pulses  given  to  the  surrounding  medium. 

Consists  of  a  flat  metal  plate  with  five  rows  of  holes  in  con¬ 
centric  circles,  four  of  which  rows  have  holes  equally  spaced 
to  sound  the  tones  C,  E,  G,  and  C',  while  the  fifth  is  un¬ 
equally  spaced  to  sound  a  “noise.” 

Disc  is  emery  finished  and  nickel-plated . $1.06 

- ,  same  as  above,  but  with  nine  rows  of  holes  in  concentric 

circles,  eight  of  which  are  equally  spaced  to  sound  the 
scale  of  C,  D,  E,  F,  G,  A,  B,  and  C',  while  the  ninth  is 
unequally  spaced  to  sound  a  “noise.” .  2.76 


No.  21-267 


21-267  AIR  IMPULSE  ATTACHMENT  for  use  with  Siren  Discs  Nos.  21-226,  21-265,  and  21-257  for 

sounding  by  air  impulses  against  the  holes,  one  or  more  notes  up  to  nine. 

This  instrument  is  an  ingenious  device  provided  with  nine  air  valves,  any  or  all  of  which  may  be 
opened  by  small  thumb  screws.  It  may  be  instantly  adjusted  to  our  Rotator.  It  is  handsomely 
finished,  positive  in  action  and  cannot  get  out  of  order.  Operated  by  blowing  or  by  air  bel¬ 
lows,  requiringTonly  a  moderate  blast.  Attachment  only . $2.65 


No.  21-280 


No.  21-290 


No.  21-295 


21-280  CROVA’S  DISC  AND  METAL  SHIELD  for  attaching  to  Rotator  to  illustrate  compressional  waves. 

The  apparatus  consists  of  two  parts,  —  a  heavy  cardboard  disc  11  inches  in  diameter,  on  the 
face  of  which  are  drawn  progressively  eccentric  circles,  and  a  flat  metal  shield  12  inches  in  diameter 
with  special  clamp  for  attaching  to  a  rotator.  A  slot  cut  along  a  radius  of  the  shield  exposes  a 
narrow  strip  of  the  card  showing  short  sections  of  the  eccentric  circles.  When  the  card  is  rotated 


these  short  sections  show  alternate  expansion  and  compression.  Complete . $2.45 

21-280a  FLAT  METAL  SHIELD  with  ATTACHED  CLAMP .  2.26 

21-280b  CROVA’S  DISC,  heavy  cardboard,  11  inches  diameter . 20 


21-290  CUBICAL  OR  ROTATING  MIRROR,  for  attachment  to  Rotator  for  study  of  reflection  from  a 
Rotating  Mirror  or  for  Manometric  Flame  images. 

This  design  consists  of  four  mirrors,  one  fastened  firmly  to  each  of  the  four  vertical  sides  of  a  cubical 
box,  to  the  under  side  of  which  is  attached  an  accurately  centered  spindle  for  fastening  to  socket 

of  rotator.  All  parts  finished  dead  black .  3.15 

21-295  KOENIG’S  MANOMETRIC  FLAME  CAPSULE  for  transmitting  the  motion  of  sound  waves  to  gas 
flame,  which  by  their  pulsations  indicate  the  nature  of  sound. 

This  design  consists  of  two  metal  castings,  between  which  is  sealed  a  membrane.  One  casting  is 
provided  with  jet,  other  with  mouth-piece  and  connecting  tubing.  The  whole  is  mounted  on  a 
gas  tube  attached  to  a  substantial  metal  base. 

Complete  as  illustrated .  2.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


83 


No.  21-300 


Patent  Pending 


No.  21-300  (Sectional  View) 


21-300  REVOLVING  MIRROR,  WITH  POSITIVE  SPEED  GOVERNOR.  To  meet  the  repeated  demands 
for  a  mirror  which  may  be  revolved  at  varying  speed  and  of  a  size  sufficiently  large  for  ordinary 
laboratory  work  we  have,  after  considerable  experimentation,  devised  the  above  illustrated  method. 

This  mirror  is  self-contained  in  that  the  power  is  contained  in  the  base  in  the  form  of  a  battery  motor, 
with  “start”  and  “stop”  key.  We  secure  a  positive  speed,  governed  by  means  of  a  simple,  ef¬ 
fectively  operating  device  noted  above  the  mirror  shaft.  We  are  able  to  secure  with  this  device 
speeds  varying  from  a  few  revolutions  per  minute  up  to  4000,  the  maximum  speed  of  the  motor. 
This  variation  in  speed  may  be  made  during  the  revolution  of  the  mirror  simply  by  a  movement  of 
the  milled  screw  over  the  axle. 


As  may  be  noted  this  design  consists  of  a  metal  housing  which  serves  also  as  a  substantial  base.  Cast 
to  this  housing  is  an  upright  with  projecting  arm.  The  mirror  is  mounted  in  metal  castings 
carefully  centered.  The  metal  housing  is  provided  with  binding  posts  for  connections  to  the 
motor  and  also  with  “start”  and  “stop”  key.  The  whole  is  finished  in  nickel  and  black  oxidized, 
presenting  a  handsome  appearance.  It  will  be  found  efficient  for  all  general  work  for  which  a 
rotating  mirror  is  used . 


$9.76 


21-306 


21-310 


No.  21-306 


ARAGO’S  MAGNETIC  ROTATION  APPARATUS,  for  demonstrating 
the  reaction  between  the  electric  currents  induced  in  a  rotating  copper 
disc  and  a  magnet,  illustrating,  also,  the  damping  effect  of  copper  upon 
a  magnetic  needle. 

The  apparatus  consists  of  a  metal  casting  which  may  be  attached  to  our 
rotator  as  illustrated,  and  which  carries  adjustable  arms  for  support¬ 
ing  a  clear  glass  plate  with  beveled  edges.  Fastened  at  the  center  of 
this  glass  plate  is  a  small  support  for  the  Magnetic  Needle.  The  appa¬ 
ratus  is  finished  in  lacquered  brass  and  bright  japan. 

As  the  copper  disc  is  rotated,  the  Magnetic  Needle  is  deflected  in  the  di¬ 
rection  of  the  rotation,  and  if  the  speed  is  fairly  great,  the  needle  will 
be  dragged  completely  around  so  that  it  is  set  in  rotation.  When  the 
rotation  is  stopped  the  damping  effect  of  the  copper  is  strikingly  no¬ 
ticed. 


Apparatus  complete  as  illustrated,  ready  for  attachment  to  our  rotator . $5.86 

EARTH  INDUCTION  APPARATUS,  for  mounting  to  the  socket  of  a  rotator  to  illustrate  induced 
currents  set  up  in  a  coil  of  wire  by  the  inductive  action  of  the  earth. 

This  apparatus  consists  of  a  closed  coil  of  wire  wound  on  metallic  frame,  provided  with  com¬ 
mutator  and  brushes,  ready  for  attachment  to  a  rotator .  6.86 


S4 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


THE  HARCOURT 


UNIVERSAL  GYROSCOPE 


No.  21-340 

Patent  Pending 


It  is  with  much  satisfaction  that  we  list  here  this  valuable  series  of  instruments  for  demonstrating  gyroscopic 
phenomena. 

The  plan  on  which  these  instruments  are  designed  is  that  of  using  the  simple  unit  to  demonstrate  the  simpler 
forms  of  gyroscopic  action  and  to  build  up  from  this  unit  a  complete  line  of  accurate  and  well-worked-out  gyroscopes- 

If  it  is  not  possible  to  purchase  the  complete  outfit  at  once,  the  simple  element  with  stand  may  be  purchased 
at  first,  and  other  features  added  at  will  until  the  complete  system  is  obtained.  By  this  plan,  a  full  set  of  gyroscopes 
may  be  obtained  at  much  less  cost  than  the  separate  instruments. 

THE  BASIC  UNIT.  This  consists  of  a  perfectly  balanced  wheel  inches  in  diameter,  so  designed  that  the 
mass  is  kept  as  near  the  periphery  as  possible. 


DETAILED  FEATURES 

LOCK-NUT  on  Basic  Unit.  The  method  of  holding  the  wheel  in  its  gimbal  ring  is  unique,  in  that  the  lock-nut 
is  so  placed  that  it  serves  to  prevent  the  power  string  from  catching  in  the  bearing  when  in  use. 

UNIVERSAL  BEARING  POST.  A  convenient  and  well-designed  reversible  bearing  post  is  fitted  to  the  base 
standard.  It  serves  the  multiple  purpose  of  providing  a  suitable  pivotal  bearing,  a  thread  post  for  attaching  any 
of  the  rings,  and  a  cup  support  for  the  ball-bearing  on  the  end  of  the  main  axle. 

UNIVERSAL  GIMBAL  BEARING.  A  valuable  adaptation  of  the  gimbal  bearing  worked  out  by  E.  S.  Ritchie 
to  give  the  greatest  freedom  of  motion  with  the  least  friction.  The  use  of  this  bearing  is  well  illustrated  in  the  build¬ 
ing  up  of  both  the  COUNTERPOISED  and  the  BOHNENBERGER  types  of  instruments. 

The  various  parts  going  to  make  up  the  complete  outfit  may  be  briefly  stated  as  follows- 

1  STAND,  UNIVERSAL  ROD  with  Cone  and  Cup  Bearings. 

2  ROTATING  WHEEL  SYSTEMS  (BASIC  UNITS). 

1  EXTENSION  ROD  WITH  COUNTERPOISE. 

1  EXTENSION  ROD  STILT  ATTACHMENT. 

1  GIMBAL  RING  AND  BEARING. 

1  BOHNENBERGER  RING  AND  BEARING. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


85 


It  will  thus  be  seen  that  from  the  basic  unit,  by  the  addition  of  accessory  parts,  we  are  able  to  assemble  all  forms 
illustrated  below.  For  example: — 

In  order  to  assemble  the  SIMPLE  GYROSCOPE  No.  21-360,  use  the  Supporting  Stand  with  Universal  Cone  and 
Cup  Bearing  and  the  Basic  Unit. 

To  assemble  the  COUNTERPOISE  GYROSCOPE,  No.  21—366,  the  only  additional  parts  would  be  the  Exten¬ 
sion  Rod  and  Counterpoise,  together  with  the  Gimbal  Bearing,  if  desired. 

To  assemble  the  BOHNENBERGER  GYROSCOPE,  No.  21-360,  only  the  Bohnenberger  Ring  need  be  pro¬ 
vided  in  addition  to  the  above. 

The  COMPOUND  GYROSCOPE,  No.  21-346,  requires  one  extra  Basic  Unit. 

The  Extension  Rod  Stilt  Attachment  supplied  with  each  outfit  enables  one  to  set  up  the  STILT  GYROSCOPE 
(not  listed  or  illustrated  below)  for  illustrating  the  resistance  exerted  by  a  spinning  gyroscope  in  the  monorail  to  wind 
pressure,  causing  the  whole  carriage  to  lean  over  toward  the  wind  and  to  lean  more  and  to  increase  its  resistance  in 
exactly  the  same  ratio  as  the  force  of  wind  increases. 

It  will  thus  be  seen  that  the  cost  of  the  Gyroscopic  Outfit  in  this  form  will  be  much  less  than  the  cost  of  the 
individual  instruments  furnished  complete.  This  is  our  reason  for  strongly  advising  the  purchase  of  one  complete 
outfit,  if  possible. 

21-340  GYROSCOPIC  OUTFIT  complete  as  listed . . $17.45 

Note.  —  Great  care  is  exercised  in  testing  out  all  of  the  parts  with  their  intei changeable  features  before  the  instruments  are  shipped. 


21-345  FESSEL’S  COMPOUND  GYROSCOPE.  This  Gyroscope  consists  of  two  of  the  Basic  Units  de¬ 
scribed  on  the  preceding  page,  mounted  on  stand  as  illustrated.  We  desire  to  call  attention  to  the 
fact  that  with  the  purchase  of  this  Compound  Gyroscope,  simple  gyroscopic  action  as  illustrated 
under  No.  21-360  may  be  demonstrated  by  dissembling  the  Compound  Gyroscope  and  using  the 

parts  as  illustrated . $11.00 

21-350  BOHNENBERGER’S  GYROSCOPE.  This  Gyroscope,  as  may  be  readily  noted,  consists  of  our 
Basic  Unit  with  the  addition  of  the  Bohnenberger  Ring  and  Bearing.  It  will  be  noted,  also,  that 
this  Gyroscope  may  be  dissembled  and  used  in  demonstrating  simple  gyroscopic  phenomena  as  il¬ 
lustrated  under  No.  21-360  .  8.75 

21-355  COUNTERPOISE  GYROSCOPE,  assembled  as  illustrated  from  the  Simple  Gyroscope  Basic  Unit, 
Extension  Rod  and  Counterpoise,  Gimbal  Ring  and  Bearing,  and  mounted  on  a  Stand  with  Uni¬ 
versal  Bearing  Post .  7.60 


No.  21-345 


No.  21-360 


No.  21-355 


Fig.  1  No.  21-360  Fig.  2 

21-360  SIMPLE  GYROSCOPE,  3}4  inch  wheel.  This  instrument  is  not  a  toy,  although  the  illustrations 
depict  its  use  in  positions  as  so  frequently  advertised  by  toy  manufacturers.  Under  this  number,  we 
supply  the  Simple  Gyroscope  Basic  Unit  with  Supporting  Stand  and  Universal  Bearing  Post. 
Perhaps  no  single  instrument  is  capable  of  such  spectacular  results  as  that  of  the  Simple  Gyroscope, 
and  every  school  equipment  should  have  at  least  one,  constructed  scientifically  and  sufficiently 

massive  to  place  it  in  the  realm  of  scientific  instruments . $5.50 

21-367  SIMPLE  GYROSCOPE,  light  wheel,  usual  form .  1-90 

21-371  “SPINNING  TOPS”  by  Professor  Perry,  who,  in  a  very  simple  and  interesting  manner,  describes 

and  explains  many  interesting  experiments . Per  copy  1.26 


86 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ACTION  AND  REACTION 

BALLS 


(Used  by  special  permission  of  copyright  owners) 


Nos.  22-10  to  22-110 


PENDULUM  BALLS,  for  use  also  in  Action  and  Reaction  Experiments. 

22-10  WOODEN  BALLS: 


a 

b 

c 

d 

Diameter,  inches 

3/ 

1 

l  X 

2 

Price  . 

.  $0.06 

$0.10 

$0.12 

$0.16 

22-20 

GLASS  BALLS: 

a 

b 

c 

Diameter,  inches  . 

.  x 

1 

l  X 

Price  . 

.  $0.06 

$0.16 

$0.36 

22-30 

IVORY  BALLS,  accurately  turned,  polished,  and  with  a 

.  hole  drilled  for  suspension 

a 

b 

c 

Diameter,  inches 

1 

IX 

2 

Price  . 

.  $1.60 

$1.90 

$2.60 

22-40 

LEAD  BALLS,  made  of  cast  metal,  drilled  for  suspension: 

a 

b 

c 

d 

Diameter,  inches 

•  X 

% 

1 

IX 

Price  . 

.  $0.06 

$0.09 

$0.16 

$0.64 

22-60  BRASS  BALLS,  accurately  turned,  polished,  drilled  for  suspension: 

abed 


Diameter,  inches  ■  .  X  X  I  ^X 

Price  . $0.12  $0.17  $0.30  $0.78 

22-60  IRON  BALLS,  cast,  a,  b,  and  c  drilled  for  suspension;  d  and  e  with  hooks. 

a  b  c  d  e 

Diameter,  inches  .  .  %  1  1  X  2  3 

Price  . $0.06  $0.07  $0.13  $0.20  $0.60 

22-61  MASSIVE  IRON  BALL  WITH  THREE  HOOKS . 

22-70  HIGHEST  GRADE  STEEL  BALLS,  hardened,  accurately  ground  and  polished.  There  are  no  holes, 
but  the  small  balls  may  be  suspended  by  shellacing  a  thread  to  them. 

a  b  c  d  e  f 

Diameter,  inches  .  .  %  X  X  1  ^X  2 

Price  . $0.04  $0.06  $0.09  $0.20  $0.40  $1.10 

22-72  STEEL  BALLS,  with  loop  attachment  for  suspension,  1  inch  diameter . 

22-80  FINISHED  LIGNUM -VITAE  BALLS,  IX  inches  in  diameter . 

22-90  COPPER  BALLS,  not  turned  but  drilled  for  suspension: 


a  b  c 

Diameter,  inches  .  .  X  1  IX 

Price  . $0.22  $0.33  $0.67 

22-100  CORK  BALLS,  lathe  turned,  and  drilled  for  suspension: 

a  b  c 

Diameter,  inches  .  .  X  1  ^X 

Price  . $0.06  $0.10  $0.20 


22-110  COMBINATION  SET  OF  BALLS,  for  use  in  collision  experiments,  giving  a  variety  of  weights  with 
approximately  the  same  size.  The  set  consists  of  \X  inch  balls  of  cork,  ivory,  lignum- vitae, 
glass,  iron,  brass,  copper  and  lead . Set 


$0.70 


$0.60 

.30 


$4.20 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


87 


ACTION  AND  REACTION 

IMPACT  SECOND  LAW  OF  MOTION 


In  this  place,  we  desire  to  call  attention  to  the  fact  that  we  have,  wherever  practical,  discarded  wood  sup¬ 
ports,  using  in  all  our  designs  special  castings  made  from  expensive  patterns.  This  line,  therefore,  will  be  found 
practically  indestructible.  It  is  scientific  in  appearance  and  any  laboratory  may  well  be  proud  of  a  thorough  equip¬ 
ment.  Each  casting  is  uniformly  smooth  and  appropriately  finished.  Wherever  a  clamp  is  a  part  of  the  casting, 
the  screw  is  heavily  nickel-plated.. 


22-130  UNIVERSAL  STAND.  It  will  be  noted  from  this  point  on,  that  frequent  use  is  made  of  a  Support 
Rod  mounted  in  a  Tripod  Base.  We  desire  to  call  attention  to  the  extreme  utility  of  this  stand. 

Besides  forming  a  rigid  support  for  various  accessories  illustrative  of  the  Laws  of  Mechanics  under 
discussion,  it  presents  a  handsome  appearance  and  will  support  practically  all  of  our  accessories 
illustrated  in  the  following  pages.  It  consists  of  our  No.  5-20e  Support  Rod,  100  centimeters  long, 

19  millimeters  diameter,  and  our  No.  5-155  Tripod  Base. 

We  list  it  herewith  as  a  unit,  that  we  may  emphasize  its  extreme  utility.  Complete  as  illustrated  .  $2.10 


22-131  UNIVERSAL  STAND,  same  as  above,  but  tripod 

provided  with  three  leveling  screws  ....  $3.15 


22-136 

s  n>. 

-d 


IMPACT  APPARATUS,  illustrating  by  impact 
of  equal  masses  the  resolution  of  one  force  into 
two  equal  forces. 

The  apparatus  consists  of  a  casting  with  clamp 
for  attaching  to  our  Universal  Support  No. 
22-130.  This  casting  is  provided  with  friction 
taper  plugs  for  holding  the  balls  of  equal  masses 
in  bi-filar  suspensions.  At  rest,  the  lengths 
of  these  suspensions  should  be  adjusted  so 
that  the  balls  just  touch  each  other. 

By  impact  of  one  ball  simultaneously  against  the 
other  two,  it  will  be  noted  that  each  of  the  im¬ 
pinged  balls  is  forced  a  distance  equal  to  half 
that  which  the  impinging  ball  traversed. 

Complete  as  illustrated,  ready  for  attachment  to 
rod  of  Universal  Stand . 


No.  22-130 


No.  22-135 


88 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  22-145 


22-145  IMPACT  AND  REFLECTION  ATTACHMENT  for  determining  the  laws  of  impact,  also  for  de¬ 
termining  law  of  incidence  and  reflection  of  light. 

This  attachment  consists  of  a  special  clamp  casting  to  which  is  firmly  fastened  the  graduated  half¬ 
circle  disc  of  wood.  As  a  part  of  this  casting,  is  an  impact  plate  and  “boss.”  To  the  latter  are 
swiveled  two  arms,  one  of  which  is  equipped  with  a  spring  gun,  designed  to  project  a  ball  against 
the  impact  plate,  the  other  with  stop  for  receiving  ball  after  rebound  from  impact  plate. 

By  setting  the  arm  carrying  the  spring  gun  at  some  position  and  projecting  the  ball  against  the 
plate,  it  will  be  found  that  the  stop  will  have  to  be  moved  to  a  similar  position  on  the  other  side  of 
the  normal  line. 

A  simple  attachment  making  this  apparatus  of  greater  utility  is  provided  on  the  spring  gun  arm. 

This  consists  of  an  upright  with  sight  hole.  If  a  lighted  candle  is  placed  in  the  stop,  which  is  de¬ 
signed  for  this  double  purpose,  and  a  mirror  attached  to  the  impact  plate,  it  will  be  found  that  the 
sight  hole  will  have  to  be  moved  to  a  similar  position  on  the  other  side  of  the  normal  to  receive 
the  reflection  of  the  candle. 

Attachment  complete  as  illustrated,  with  the  addition  of  a  Mirror  for  determining  the  law  of  inci¬ 
dence  and  reflection  of  light . $6.65 


NOTE.  ACCESSORY  APPARATUS  NEEDED 

22-130  UNIVERSAL  SUPPORT . .  $2.10 

CANDLES.  See  Index. 


No.  22-160 


22-160  ACTION  AND  REACTION  APPARATUS  for  quantitative  demonstration  that  Action  is  equal 
but  opposite  to  Reaction  when  two  elastic  bodies  impinge. 

The  apparatus  consists  of  a  mounted  Meter  Stick  on  which  are  placed  and  clamped,  where  desired, 
two  ingenious  detents.  Two  ivory  balls  suspended  from  any  convenient  hanger  rest  against  these 
detents  and  are  released  by  a  sudden  pull  on  a  string  which  drops  the  detents,  thus  allowing  the 
balls  to  fall  towards  each  other,  starting  at  the  same  instant. 

Complete  apparatus  as  listed  separately  below . $5.50 

22-160a  METER  STICK,  with  loop  for  string .  .33 

22-160b  METAL  SUPPORTS  for  Meter  Stick . Per  Pair  .25 

22-160c  DETENTS  ready  for  attachment  to  Meter  Stick . Per  Pair  .60 

22-160d  IVORY  BALLS,  two  of  different  masses  .  .’ . Per  Pair  4.40 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


89 


No.  22-180  No.  22-190 


COLLISION  BALL  APPARATUS,  IMPROVED  FORM,  for  the  quantitative  and  qualitative  study  of  im¬ 
pinging  elastic  bodies. 


The  apparatus  consists  of  a  rectangular  metal  frame  of  special  design  for  attachment  to  our  Universal  Stand 
No.  22-131.  Ten  steel  balls,  1  inch  in  diameter  and  one  steel  ball  four  times  the  mass  of  each  of  the  others  are  at¬ 
tached  to  this  frame  by  stout  silk  cords  and  held  adjustably  to  it  by  tapering  plugs.  As  each  ball  is  held  in  a  bi-filar 
suspension,  the  directive  force  of  impact  is  at  the  will  of  the  operator  simply  by  turning  the  tapering  plugs.  A  special 
design  graduated  arc  is  necessary  for  quantitative  work.  This  arc  is  made  to  attach  directly  to  the  Universal  Stand 
No.  22-131.  The  lines  and  figures  being  especially  clear,  they  may  be  seen  from  the  rear  of  any  lecture  room. 


22-180  COLLISION  BALL  APPARATUS,  complete  with  No.  22-131  Universal  Stand,  Rectangular  Attach¬ 
ment  with  ten  steel  balls,  1  inch  in  diameter,  and  one  steel  ball  of  four  times  the  mass  of  each 


of  the  others,  and  with  Graduated  Arc  with  Clamp  for  attachment  to  the  Universal  Stand  .  .  $14.76 

22-181  RECTANGULAR  FRAME  with  CLAMP,  including  all  balls,  listed  above .  9.86 

22-182  GRADUATED  ARC  with  CLAMP  as  used  in  No.  22-180  .  2.60 

22-131  UNIVERSAL  STAND .  3.16 

22-190  COLLISION  BALL  APPARATUS  for  study  of  impinging  elastic  bodies. 

This  apparatus  consists  of  a  rectangular  frame  similar  in  general  construction  to  that  used  above 
but  designed  for  suspending  five  lignum-vitse  balls,  each  in  bi-filar  suspension.  The  apparatus 
illustrated  is  designed  to  clamp  over  any  19  millimeter  rod. 

Rectangular  Frame  with  the  five  balls  attached .  3.86 


90 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  22-200 


No.  22-220 


No.  22-226 


22-200  MOMENTUM  APPARATUS  for  deriving  laws  of  momentum. 

This  apparatus  is  designed  for  attachment  to  our  Universal  Support  No.  22-131.  It  consists  of  a 
rectangular  metal  frame  supporting  in  bi-filar  suspension  two  bodies  with  masses  of  the  ratio  1:  4. 

The  larger  body  has  a  special  ingenious  spring  striking  attachment  operative  on  both  bodies  at 
the  same  time.  In  operation,  this  striking  attachment  is  pulled  back  against  the  spring  and 
held  by  a  piece  of  string.  When  this  string  is  burned  a  blow  is  given  to  the  smaller  body  which 
is  communicated  to  the  larger  at  the  same  time. 

The  complete  apparatus  consists  of  the  Rectangular  Frame  Momentum  Attachment,  the  Universal 

Support  No.  22-131  and  a  Graduated  Arc.  Complete  apparatus . $11.00 

22-201  MOMENTUM  ATTACHMENT  only .  6.66 

22-182  GRADUATED  ARC  WITH  CLAMP  for  attachment  to  a'  19  millimeter  rod .  2.60 

22-220  SECOND  LAW  OF  MOTION  APPARATUS  consisting  of  a  flexible  hardwood  strip  about  15  inches 
long  and  a  vise  for  attaching  one  end  firmly.  The  hardwood  strip  has  a  right  angle  head  with  a 
notch  at  each  upper  end  in  which  are  placed  small  marbles. 

In  use,  the  marbles  are  placed  in  position  in  their  respective  notches;  the  flexible  strip  is  then  bent 
to  one  side  and  released.  One  marble  will  shoot  out  horizontally,  while  the  other,  owing  to  its 
inertia,  will  drop  automatically,  at  the  same  instant  taking  the  course  of  a  straight  line,  thus  dem¬ 
onstrating  the  Second  Law  of  Motion. 

Complete  with  Vise .  1.46 


22-221  BENCH  VISE  CLAMP  as  used  in  No.  22-220  .  1.00 

22-222  FLEXIBLE  HARDWOOD  STRIP  as  used  in  No.  22-220  . 46 

22-226  SECOND  LAW  OF  MOTION  APPARATUS.  This  design,  above  illustrated,  is  one  simplified  for  use 
in  the  hand.  The  length  of  the  rod  is  such  that  when  rod  and  attached  ball  are  pulled  against  the 
spring  and  then  allowed  to  be  propelled  from  the  tube,  the  second  ball  will  drop  from  the  rod  at 
the  same  instant  as  the  ball  and  rod  leave  the  tube,  both  reaching  the  floor  at  the  same  in¬ 
stant,  although  one  drops  in  a  plumb  line  and  the  other  describes  a  parabolic  path .  2.90 

22-230  GAGE’S  SECOND  LAW  OF  MOTION  APPARATUS. 

This  apparatus  consists  of  a  metal  casting  holding  a  rod  actuated  by  a  spring.  Two  spheres  are 
provided,  one  solid  while  the  other  is  drilled  for  slipping  over  one  end  of  the  rod  when  the  spring 
is  held  back  for  releasement.  The  solid  sphere  is  placed  in  position  as  illustrated,  so  that  when 
the  spring  is  released  the  end  of  the  rod  will  inflict  a  blow  upon  it,  shooting  it  out  in  a  horizontal 
position.  The  rod  is  of  such  length  that  when  the  spring  is  released  the  drilled  ball  will  drop  at  the 
same  time  as  the  solid  ball  receives  its  blow.  It  will  be  observed  that  the  solid  ball  describes  a 
parabola  while  the  drilled  ball  drops  in  a  plumb  line,  both  reaching  the  floor  at  the  same  instant. 

In  use  this  apparatus  should  be  firmly  attached  to  a  heavy  wooden  block  or  to  a  table  top  ....  2.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


9i 


STRESS  AND  STRAIN 

TORSION  OF  BEAMS  TORSION  OF  WIRES  ROTATIONAL  VIBRATION 
FLEXURE  OF  BEAMS  YOUNG’S  MODULUS 
TENSILE  STRENGTH  OF  WIRES 


23-10  HARCOURT  T-BEAM  TORSION  APPARATUS  for  determining  the  moment  of  torsion  and  the 
coefficient  of  torsional  rigidity  of  rods  of  different  lengths  and  different  diameters.  The  above  il¬ 
lustration  shows  the  adaptability  and  interchangeability  of  our  Universal  T-Beam  Series.  (Sec¬ 
tion  6.) 

The  distinctive  torsion  parts  consist  of  a  ball-bearing  Torsion  Wheel  (No.  5-1175),  in  the  hub  of  which 
the  movable  end  of  the  rod  may  be  centered  and  rigidly  fixed  by  set  screws.  The  other  end  of 
this  rod  is  firmly  fastened  in  a  similar  manner  in  the  Fixed  Head  Torsion  of  Beams  Attachment 
(No.  5-1180).  The  twist  on  the  rod  so  fastened  is  secured  by  weights  attached  to  a  steel  ribbon 
wound  about  the  flat  face  of  the  torsion  wheel.  The  length  of  the  rod  under  experimentation  may  be 
arbitrarily  determined  by  the  positions  of  the  Index  Arcs  and  Pointers;  the  former  secured  by  move¬ 
ment  of  the  clamp  on  the  table;  the  latter  by  movement  of  the  Pointers  along  the  rod.  The  Index 
Arcs  have  interlocking  attachments  for  use  on  our  T-Beam  Basic  Clamp  “A”.  The  Pointers  are 
fastened  to  the  rod  by  set  screws. 

It  will  be  noted  that  this  design  obviates  errors  due  to  slipping  of  the  rods  at  the  points  where 
they  are  clamped. 

Complete  apparatus,  without  clamps  and  without  hanger  and  weights  but  including  four  rods;  steel, 

3  mm.  and  6  mm.  in  diameter,  brass,  3  mm.  and  6  mm.  in  diameter  ....  . $9.16 

The  Basic  Clamps  used  in  above  illustration  are: 

5- 1000  T-BEAM  BASIC  CLAMP  “A”  (two  required)  .  .  Each  $0.94 

6- 1150  T-BEAM  BASIC  CLAMP  “B”  (two  required)  .  .  Each  1.65 

23-16  HARCOURT  TORSION  APPARATUS.  This  apparatus  is  the  same  as  above  in  design  except  that  the 
Torsion  Wheel,  the  Fixed  Head  and  the  Arcs  are  cast  as  parts  of  the  table  clamps.  It  is  offered 
to  those  teachers  who,  unfortunately,  do  not  have  in  their  laboratories  a  system  of  T-BEAM  BASIC 
CLAMPS  and  INTERLOCKING  ATTACHMENTS.  Complete  with  four  rods,  —  steel,  3  mm. 
and  6  mm.  in  diameter,  and  brass,  3  mm.  and  6  mm.  in  diameter . 13.35 


WEIGHTS.  Section  16. 


92 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  23-30 


23-30  SIMPLE  TORSION  APPARATUS  for  deriving  laws  of  torsion. 

Complete  apparatus,  as  listed  below,  including  two  spring  balances . $2.46 

23-30a  ASH  ROD,  V2  X  Vi  inch . 12 

23-30b  - ,  %  X  %  inch . 14 

23-30c  COMBINATION  BASE  LEVER . 60 

23-30d  GUIDE  PIVOT . . . „ . 26 

23-30e  IRON  CLAMP  FOR  ROD . 35 

14-46  QUARTER  CIRCLE  PROTRACTOR . 09 

16-310  SPRING  BALANCE . 45 


Nos.  23-60  and  23-62 


23-60  IMPROVED  SABINE’S  TORSION  PENDULUM  for 

determining  the  moment  of  torsion  of  a  wire  and  the 
moment  of  inertia  of  a  ring. 

The  design  illustrated  obviates  the  annoyances  of  existing 
types.  It  is  simple  in  design,  self-contained,  and  sci¬ 
entific  in  structure  and  appearance.  Accurate  results 
are  possible  with  a  minimum  of  trouble. 

Two  methods  of  reading  torsional  vibrations  are  possible, 
—  by  direct  observation  of  consecutive  transits  of  the 
index  past  the  zero  point  of  the  graduated  arc;  by  ob¬ 
serving  through  a  telescope  the  consecutive  flashes 
from  the  illuminated  mirror. 

The  disc  is  10)4  inches  in  diameter  and  is  clamped  to  the 
wire  by  means  of  a  small  chuck  fixed  at  its  middle  point. 

This  disc  is  then  supported  from  the  frame  by  a  similar 
chuck  having  the  additional  features  of  an  adjusting 
thumb  nut  and  a  set-screw.  The  index  dial  is  cast  from 
metal  and  has  large  raised  figures.  A  ring  moment 
of  inertia  of  which  is  to  be  determined  has  the  same 
diameter  and  mass  as  the  disc. 

Torsion  pendulum,  as  illustrated  but  without  mirror 


attachment .  . $16.60 

23-62  MIRROR  ATTACHMENT  complete,  ready  for  attach¬ 
ment  as  illustrated .  1-26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


93 


No.  23-90 


23-60  TORSION  PENDULUM  for  determining  the  moment  of  torsion  for  a  steel  wire  and  the  moment 
of  inertia  of  two  iron  weights. 

The  apparatus  consists  of  a  metal  frame  mounted  to  one  of  our  substantial  H  bases.  Suspended  from 
the  central  part  of  this  frame  by  means  of  a  simple  chuck  is  the  suspension  system  consisting  of  a 
steel  wire  at  the  end  of  which  is  mounted  a  cross  head  carrying  two  disc-shaped  metal  weights  fixed 
adjustably  along  the  cross  head. 

Complete  as  illustrated . $  4.50 

23-62  TORSION  SYSTEM  as  used  in  above  frame,  all  that  is  required  if  No.  23-60  or  23-100  is  a  part  of 

the  school  equipment .  2.26 

23-90  HARMONIC  MOTION  APPARATUS  for  verifying  the  Laws  of  Harmonic  Motion  (Ames  and 
Bliss,  page  111)  by  noting  the  rotational  vibrations  of  a  flat  coiled  spring. 

This  apparatus  consists  of  a  flat  coiled  spring  mounted  on  a  vertical  axis  supported  in  frictionless 
bearings,  which,  in  turn,  carries  an  arm  with  sliding  weights  to  vary  the  inertia.  The  oscillations 
are  indicated  by  a  pointer  over  a  graduated  aluminum  dial.  The  whole  is  mounted  on  a  tripod 
base  upright  supporting  the  vertical  axis  and  providing  a  support  for  a  rod  to  which  one  end  of  the 
spiral  is  fixed.  Handsomely  finished  throughout  in  bright  japan,  lacquered  brass  and  nickel-plate. 

Complete  as  illustrated . 22.00 

23-100  INERTIA  BALANCE  for  determining  the  mass  of  a  body  without  weighing. 

The  apparatus  consists  of  a  metal  frame  same  as  No.  23-60  mounted  on  our  improved  H  base.  To 
the  center  of  the  upper  and  lower  sides  are  small  chucks  carrying  a  wire  the  upper  end  of  which 
may  be  adjusted  in  length  by  means  of  a  thumb  screw  and  firmly  fixed  by  a  T  screw.  This 
wire  holds  a  small  metal  cone-shaped  pan  fixed  to  it  by  means  of  two  screws.  The  apparatus  is 
finished  throughout  in  a  manner  to  present  a  pleasing  appearance  and  is  carefully  constructed 
to  give  the  best  possible  results. 


Complete  apparatus  as  illustrated .  6.00 

23-102  INERTIA  SYSTEM  as  used  in  above  frame,  all  that  is  required  if  No.  23-60  or  23-60  is  a  part  of  the 

school  equipment .  2.76 

23-106  UNIVERSAL  RECTANGULAR  CAST  METAL  SUPPORTING  FRAME.  Frame  support  only  of 

Nos.  23-60  and  23-100  .  2.26 


No.  23-60 


94 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


FLEXURE  OF  BEAM 


APPARATUS 


> 


23—125  FLEXURE  OF  BEAM  APPARATUS.  This  “set  up’’  for  determining  by  experiment  the  laws  of 
elasticity  of  flexure  is  an  arrangement  of  our  Harcourt  Universal  T-Beam  Clamps.  (See  Section 
5.) 

Complete-apparatus  without  basic  clamps  and  weights . 

23-128  KNIFE  EDGE  CONTACT  PIECE.  This  is  a  metal  stirrup  with  knife  edge,  binding  post  and  hook. 

W  ith  the  knife  edge  resting  on  the  beam,  the  weights,  hanging  to  the  hook,  cause  a  stress  at  one 
point  only . 

23-130  SCALE  PAN . ’  ’  *  ^ 

WEIGHTS.  Section  16. 


Other  apparatus  illustrated  above  and  listed  elsewhere  is  as  follows: 

5—1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A”  (three  required) 

Each . 

23-136  FLEXURE  OF  BEAM  APPARATUS  same  as  No.  23—125  in  design  except  that  the  Knife  Edges 
are  cast  as  parts  of  the  table  clamps  and  in  place  of  the  T-Beam  Clamp  and  Micrometer  Screw, 
the  Mounted  Micrometer  Screw  No.  12-230  is  furnished.  Complete  without  weights 

23-140  FLEXURE  OF  BEAMS  AP¬ 
PARATUS  for  determining 
by  experiment  the  laws  for 
elasticity  of  flexure. 

The  apparatus  consists  of 
three  triangular  prisms, 
two  of  which  are  used  to 
support  the  rod  under  test, 
the  third  to  act  as  the  ful¬ 
crum  of  the  lever  indicator. 
A  vertically  mounted  rule 
gives  the  measure  of  the 
movement  of  the  long  arm 
of  this  lever.  The  scale 
pan  attached  directly  over 
the  short  arm  of  the  lever 
and  over  the  rod  serves  as  a 
support  for  the  weights 
which  cause  the  stress. 

Complete  apparatus  as  illustrated,  without  weights,  including  the  three  prisms,  two  pine  rods  of 
different  cross  sectional  area,  one  lever  indicator  with  supported  scale  and  scale  pan . 

23-141  SUPPORTING  TRIANGULAR  PRISMS . Per  Set  of  Three 

23-142  PINE  ROD,  100  centimeters  X  H  X  1  inch . 

23-143  - ,  100  centimeters  X  3^  X  lA.  inch . 

23-144  LEVER  INDICATOR . 

23-145  MOUNTED  INDEX  STRIP  after  Hall  Ex.  14  (No.  34) . 

11-70  MOUNTED  10-CENTIMETER  SCALE . 

23-130  SCALE  PAN . 

WEIGHTS.  Section  16. 


23-166  PAIR  OF  WOODEN  SUPPORT  BLOCKS,  after  Millikan,  Gale  and  Bishop’s  “Laboratory  Physics,” 
Experiment  13 . 

23-157  STEEL  ROD,  after  Millikan,  Gale  and  Bishop’s  “Laboratory  Physics,”  Experiment  13 . 


$6.32 


.65 

.12 


.94 

5.15 


$0.70 

.24 

.12 

.10 

.08 

.10 

.16 

.12 


.55 

.10 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


95 


23-180  HOOKE’S  LAW  and  YOUNG’S  MODULUS  APPARATUS,  for  testing 
Hooke’s  Law  and  determining  Young’s  Modulus  for  a  wire. 

This  apparatus  consists  of  two  parallel  rods  supported  on  a  tripod  with 
leveling  screws.  In  the  upper  casting  clamping  the  rods  is  a  small  metal 
chuck  for  clamping  the  upper  end  of  the  wire  to  be  tested.  In  a  hole 
in  the  center  of  the  movable  casting  is  a  second  chuck  which  is  set  into  a 
cylindrical  brass  piece  which  moves  with  very  little  play  in  this  hole. 
This  movable  casting  bears  an  accurately  adjusted  optical  lever  the  front 
feet  of  which  rest  on  a  small  table  incorporated  in  the  casting.  The  rear 
foot  rests  upon  the  carefuly  ground  top  surface  of  the  brass  piece  bearing 
the  chuck.  Three  two-kilogram  and  two  one-kilogram  weights  which  are 
supplied  with  the  apparatus  may  be  placed  on  the  weight  hanger  to 
give  the  stretching  force. 

This  apparatus  is  solidly  built  and  its  structure 
is  of  most  painstaking  type.  Accurate  results 
are  easily  obtained. 

Complete  as  described . $25.00 


23-191  MIRROR  SCALE  and  UPRIGHT  WOODEN 
SUPPORT  after  Millikan,  Gale  and  Bishop 
(Experiment  13) . 

23-192  SPRING  and  WEIGHT  HOLDER  after  Milli¬ 
kan,  Gale  and  Bishop  (Experiment  13)  .  .  . 


.80 


.20 


No.  23-180 


Nos.  23-191  and  23-192 


No.  23-225 


23-225  ELASTICITY  OF  WIRE  APPARATUS,  for  determining  the  Coefficient  of  Elasticity  of  Wire. 

Complete  apparatus  as  above  illustrated,  but  without  Spring  Balance  and  Basic  Clamp . $2.16 

SEPARATE  PARTS. 

23-226  SPOOL  SPRING  BRASS  WIRE,  No.  27 . $0.40 

23-227  T.  &  H.  STRETCHING  BLOCK  WITH  WOOD  PILLAR  AND  BRASS  BINDING  POST  ...  .90 

23-228  MARKER  CLAMP  AND  STYLUS . 20 

5-1150  T-BEAM  BASIC  CLAMP  “B” .  1.66 

16-316  SPRING  BALANCE,  15  kilos  and  30  pounds .  1.65 

23-231  MOUNTED  MILLIMETER  SCALE . 20 

16-366  SPRING  BALANCE  SUPPORTING  CRADLE . 45 


g6 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  * 


23-211  BREAKING  STRENGTH  OF  WIRES  APPARATUS,  for  measuring  the  tensile  strength  of  wires. 

This  apparatus  must  not  be  confused  with  the  various  forms  on  the  market.  It  is  designed  to  do 
all  and  more  than  the  others  will  do,  and  to  facilitate  rapid  and  accurate  determinations.  It 
is  constructed  entirely  of  metal.  The  essential  features  consist  of  cast  metal  legs,  to  which  are 
rigidly  fastened  two  nickel-plated  steel  rods  to  form  the  bed  of  the  instrument.  To  the  bed  are 
clamped  the  cradle  for  the  dynamometer  and  a  recoil  frame.  The  ring  of  the  dynamometer  slips 
over  a  peg  on  one  of  the  end  castings.  The  hook  is  attached  to  the  recoil  frame.  The  design  of 
this  recoil  frame  is  simple  and  most  effective.  It  is  a  metal  casting  provided  with  binding  device  for 
one  end  of  the  wire  whose  tensile  strength  is  to  be  tested  and  the  retaining  frame  with  buffer  for 
recoil  wedges.  Our  tension  device  consists  of  a  crank  operating  an  axle  about  which  the  wire 
winds  as  the  tension  increases.  Danger  of  recoil  of  crank  is  entirely  obviated  by  means  of  a  rachet 
and  pawl  attached  to  one  end  of  the  axle. 

Results  of  experience  have  demonstrated  that  in  this  design  we  offer  an  instrument  obviating  ob¬ 
jectionable  features  of  less  carefully  and  scientifically  designed  instruments.  Our  instrument  will 


form  a  valuable  acquisition  for  any  well  appointed  laboratory. 

Without  dynamometer . $5.00 

23-212  - ,  same  as  above,  but  with  double  scale  dynamometer,  30  pounds  and  15  kilos .  6.60 


COMPOSITION  OF  FORCES 


For  the  “set  up”  of  the  experiment  above  illustrated  no  new  apparatus  is  required.  Articles  shown  above 
are  as  follows: 

6-1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A.”  (Three 


needed) .  Each  $0.94 

5-1065  STONE’S  TENSION  CLAMP  ATTACHMENT.  (Three  needed)  .  .  Each  .48 
15-310  SPRING  BALANCE,  2000  grams  and  64  ounces.  (Three  needed)  .  .  Each  .45 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


97 


The  only  distinctive  item  shown  in  accompany¬ 
ing  illustration  is  the  following: 

24-15  STRAIGHT-GRAINED  SUPPORT  BOARD 

with  side  ledges  and  provided  with  clamp  at 
back  for  attaching  to  any  19-millimeter  rod  . 

Other  apparatus  illustrated  has  all  been  pre¬ 
viously  listed  as  follows: 

5- 1000  HARCOURT  T-BEAM  BASIC  CLAMP  “A.” 

(Three  required) . Each 

6- 1070  BALANCE  CRADLE  ATTACHMENT.  (Three 

required) . Each 

5-250  KNOTT  ADJUSTABLE  ECCENTRIC  LEVEL¬ 
ING  BASE  . 

5-20e  SUPPORT  ROD,  19  millimeters  diameter,  100 
centimeters  long . 


$2.20 


.94 


.66 


2.35 


1.00 


24-26 


Note.  —  Universal  Stand  No.  22-130  may  be  used  in  place 
of  the  last  two  items'if  so  desired. 


COMPOSITION  OF  FORCE  ATTACHMENT  for  use  on  any  19  mil¬ 
limeter  rod  in  the  study  of  equilibrium  and  composition  of  forces. 
This  attachment  consists  of  a  metal  casting  with  clamp  and  cross¬ 
head  in  one  piece.  The  cross-head  is  provided  with  hooks  for  hanging 


pulleys. 

Attachment  only,  without  pulley  or  weights  illustrated . $1.16 

ACCESSORY  APPARATUS  ELSEWHERE  LISTED: 

22-130  UNIVERSAL  STAND . $210 

27-150  BALL-BEARING  SINGLE  PULLEY.  (Two  required) 

Each  .60 

16-460  UNIVERSAL  WEIGHTS . Set  with  holder  2.75 


24-35  STONE’S  TENSION  CLAMPS  for  holding  either  a  string  or  wire  firmly  yet  adjustably;  convenient 
for  use  with  Spring  Balances  as  illustrated  in  determining  the  Parallelogram  of  Forces. 

This  clamp  consists  of  a  casting  with  jaws  wide  enough  to  fit  over  the  ordinary  Physics  Laboratory 
Table.  A  nickel-plated  T-screw  is  provided  for  firmly  fixing  to  the  table.  The  wire  is  threaded 
under  a  small  cam  lever  which  binds  or  releases  by  only  a  slight  motion  of  the  lever.  Per  set  of  three  $1.14 

Each  .38 


24-36  STONE’S  TENSION  CLAMP 


g8 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


No.  24-60 

COMPOSITION  OF  FORCES 


Items  above  illustrated  assembled  will  all  be  found  previously  listed,  and  if  already  a  part  of  the  school  equip¬ 
ment  will  not  be  needed.  They  are  as  follows: 


6-260  KNOTT  ADJUSTABLE  ECCENTRIC  LEVELING  BASE  .  . 
6-20e  SUPPORT  ROD,  19  millimeters  diameter,  100  centimeters  long 


22-130  UNIVERSAL  STANDS.  (Two  required) . Each 

6-770  RIGHT-ANGLE  CLAMPS.  (Two  required) . Each 

6-962  PULLEY  ON  ROD.  (Two  required) . Each 

16—460  UNIVERSAL  WEIGHTS . Per  Set  with  Holder 

24-16  SUPPORT  BOARD . 


$2.35 

1.00 

2.10 

.95 

.90 

2.76 

2.20 


24-60  PARALLELOGRAM  OF  FORCE  TABLE  for  use  in  either  HORIZONTAL  or  VERTICAL  POSITION 

in  deriving  Laws  of  Parallelogram  of  Forces. 

This  instrument  is  intended  for  high-grade  work  in  the  quantitative  determinations  of  the  Laws  of 
Parallelogram  of  Forces.  Built  throughout  of  metal,  it  is  extremely  substantial,  and  being  beauti¬ 
fully  nickeled  and  japanned,  presents  a  handsome  appearance.  The  apparatus  consists  of  a  smooth 
nickeled  iron  disc  35  centimeters  in  diameter,  divided  into  degrees.  It  is  mounted  in  such  a  manner 
that  it  can  be  used  in  either  a  vertical  or  horizontal  position.  Frictionless  bearing  brass  pulleys 
are  provided  for  attachment  to  the  edge  of  the  disc.  By  the  use  of  a  special  centering  arrangement, 
weights  and  weight  holders,  very  accurate  results  are  possible  with  this  table. 

Complete  as  illustrated,  with  three  frictionless  bearing  brass  pulleys,  centering  arrangement,  weights 


and  weight  hangers,  mounted  on  a  60-centimeter  rod  on  tripod  base .  25.00 

24-61  PARALLELOGRAM  OF  FORCE  TABLE,  same  as  No.  24-60,  but  mounted  on  a  100-centimeter  rod 

and  with  tripod  with  three  leveling  screws . .  26.00 


WEIGHTS  AND  WEIGHT  HOLDERS.  Section  16 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


99 


No.  24-80 


24-80  COMPOSITION  OF  FORCE  BOARD,  as  used  in  Millikan,  Gale  and  Bishop’s  “Laboratory 
Physics”  (Experiment  11). 

This  is  a  well-seasoned  board,  30  X  19 Yi  inches,  to  the  back  of  which  are  fastened  two  strips  of  wood, 
which  serve  the  double  purpose  of  preventing  warping  and  as  a  support.  They  are  of  sufficient 
length  so  that  the  board  may  rest  vertically.  Holes  into  which  pegs  may  be  placed  are  conveniently 
located  on  each  quarter  surface  of  the  board,  thus  providing  a  convenient  setting  for  a  pin  to  which 
strings  from  a  Spring  Balance  may  be  attached. 

The  Board,  with  three  pegs,  but  without  Balances . . $1.60 

24-87  COMPOSITION  OF  FORCE  BOARD  for  use  with  Spring  Balances  in  formulating  the  laws  of  Com¬ 
position  of  Forces. 

This  apparatus  consists  of  a  square  board  constructed  so  as  to  prevent  warping,  with  holes  equally 
spaced  in  squares.  Pins  are  provided  which  may  be  placed  in  any  hole  desired,  to  which  may  be 
attached  the  strings  from  the  hooks  of  Spring  Balances.  That  the  board  may  move  freely,  four 
spheres  are  provided,  which,  when  placed  next  to  the  retaining  rims  on  the  under  side,  will  act  as 
ball  bearings.  This  board  has  a  sandpaper  and  oil  finish  and  is  substantially  built  throughout. 


Board  with  four  pegs  and  four  balls .  1.66 

24-96  WIRE  PENTAGON,  after  Turner  and  Hersey  (Experiment  M274)  .  .16 


No.  24-100 


24-100  GAGE’S  COMPOSITION  OF  FORCE  AND  MOTION  APPARATUS  for  the  graphic  representation 
of  the  components  and  resultant  of  two  forces. 

The  apparatus  consists  of  a  flat  board  to  which  is  clamped  an  attachment  consisting  of  a  clamp 
holding  in  a  sliding  fit  a  square  rod,  with  cross  head  which  in  turn  carries  a  slide  with  pencil  clamp. 

This  pencil  clamp  is  free  to  move  along  a  rod  parallel  to  the  cross  head  and  is  connected  by  a  string 
around  a  pulley  to  the  end  of  the  arm  attached  to  the  clamp  holding  the  apparatus  to  the  board. 

Results  possible  with  this  apparatus  arouse  the  interest  of  pupils  in  the  Resolution  of  Forces.  It  is 
pedagogically  superior  to  much  that  is  on  the  market  for  the  graphic  representation  of  forces. 

Complete  as  illustrated . $9.76 


100 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


FORCE  OF  GRAVITATION 

EQUILIBRIUM  —  Stable,  Unstable  and  Neutral 


No.  25-65 


No.  26-10 


No.  26-15 


No.  26-50 


1.35 


.76 


25- 10  CENTER  OF  GRAVITY  BOARD  for  determining  the  center  of  gravity  of  an  irregularly-shaped  board. 

This  apparatus  consists  of  a  board  of  irregular  shape  drilled  at  various  points.  If  the  board  is  held 
suspended  from  these  several  points,  and  a  plumb  line  dropped  from  each,  it  will  be  found  that 
these  lines  all  intersect  at  one  point,  —  the  center  of  gravity. 

Board  complete  with  handle  support  and  plumb  bob . $0.95 

26- 16  MOUNTED  CENTER  OF  GRAVITY  ARC  for  illustrating  stable  and  unstable  equilibrium. 

This  apparatus  consists  of  a  balanced  system  so  designed  that  the  center  of  gravity  may  be  readily 
adjusted  to  demonstrate  stable,  unstable  and  neutral  equilibrium. 

Complete  as  illustrated,  with  supporting  stand  . , . 

25- 20  CENTER  OF  GRAVITY  SYSTEM  for  illustrating  the  center  of  gravity. 

The  apparatus  consists  of  two  brass  spheres  of  different  sizes  connected  by  a  rod  in  which  are  drilled 
two  holes,  one  at  the  geometric  center,  the  other  at  the  center  of  gravity.  A  support  handle  is 
supplied  with  each  instrument. 

Complete  as  illustrated  . . . 

26- 60  LOADED  CYLINDER  WHEEL  for  illustrating  the  center  of  gravity  of  a  loaded  wheel. 

This  apparatus  consists  of  a  wooden  disc  loaded  near  the  edge  and  drilled  at  the  geometric  center 

and  at  the  center  of  gravity.  A  suitable  upright  for  support  is  also  furnished .  1.20 

25- 55  LOADED  CYLINDER,  illustrating  the  tendency  of  a  body  to  place  its  center  of  gravity  as  low  as 

possible. 

This  is  a  wooden  cylinder  loaded  eccentrically,  which,  if  rolled  along  a  horizontal  surface,  will  strive  to 
rest  on  its  loaded  side . 

26- 60  WITCH,  illustrating  the  tendency  of  a  body  to  keep  its  center  of  gravity  as  low  as  possible. 

This  apparatus  consists  of  a  hemispherical  piece  of  metal  to  which  is  attached  a  short  length  of  pith. 

26-76  LEANING  TOWER,  illustrating  stability  when  a  line  drawn  through 
the  center  of  gravity  comes  within  base  of  support. 

This  inexpensive  device,  illustrative  of  the  celebrated  Leaning  Tower 
of  Pisa,  is  built  of  wood  with  a  removable  top  and  foot.  With  the  foot 
in  place,  the  tower  will  stand 
so  that  its  center  of  gravity  is 
in  center  of  circle  of  the  base. 

With  foot  removed  and  top  in 
place,  the  center  of  gravity 
being  without  the  base,  the 
tower  will  topple  over.  With 
top  taken  off,  the  tower  will 
stand  stable,  the  center  of 
gravity  coming  within  the 
base . 1  .  . 


.30 

.11 


$1.20 


No.  26-80 


No.  26-76 

26-80  HORSE  AND  RIDER,  illustrating  equilibrium  when  line  drawn 
through  the  center  of  gravity  comes  within  base  of  support. 

The  apparatus  consists  of  wooden  figures  representing  a  horse 
and  rider.  A  wooden  ball  is  attached  to  the  figures  so  that 
its  weight  changes  the  center  of  gravity  to  come  within 
the  base  of  support.  A  striking  illustration  of  the  principle 
is  possible  as  pictured . 


.95 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


IOI 


FALLING  BODIES 

ACCELERATED  MOTION 


No.  26-100 

Patented  December  17,  1907 


26-100  PACKARD’S  FALLING  BODY  APPARATUS  for  the  determination  of  the  Laws  of  Accelerated 
Motion  with  their  application  to  falling  bodies,  the  data  being  obtained  from  the  path  that  the 
falling  body  traces  during  descent. 

This  ingenious  invention  of  Mr.  John  C.  Packard  of  the  Brookline  High  School,  Brookline,  Mass., 
is,  in  its  fundamental  principle,  a  greatly  improved  inclined  plane.  It  consists  of  a  board  of  a 
design  to  meet  the  special  requirements.  A  quick-acting  spirit  level  is  attached  for  obtaining  the 
*  necessary  plumb  in  one  plane.  Adjustable  legs  at  one  end  afford  facilities  for  varying  the  angle 
of  tilt  for  changing  the  conditions.  In  use,  a  steel  ball  is  allowed  to  roll  down  over  the  smooth 
surface  of  a  sheet  of  paper  covered  with  a  soft  carbon  tracing  paper.  There  will  be  found  on  the 
board,  effective  devices  for  clamping  the  paper  and  for  holding  and  releasing  the  ball  as  required. 
Results  obtained  by  even  the  most  careless  students  are  ample  recommendations  for  the  purchase 
of  this  instrument. 

Complete  with  12  sheets  Cross-section  Paper  and  2  sheets  Carbon  Paper.  Special  circular  on  re¬ 


quest  .  $6.26 

26-101  CROSS-SECTION  PAPER,  special  ruled . Per  Ten  Sheets  .30 

26-102  CARBON  PAPER,  especially  adapted  for  use  with  No.  26-100  . Per  Sheet  .07 


26-106  DUFF’S  ACCELERATION  APPARATUS,  designed  by  Dr.  A.  Wilmer  Duff  of  Worcester  Polytechnic 
Institute,  for  determining  the  acceleration  of  a  falling  body. 

The  apparatus  consists  of  an  accurately  grooved  plank.  With  the  plank  placed  horizontally  on  the 
table,  a  steel  ball  placed  on  one  end  of  the  groove  will,  when  released,  oscillate  back  and  forth 
like  a  pendulum  and  the  time  of  each  swing  will  remain  constant.  If,  however,  one  end  of  the 
plank  be  raised  a  little  higher  than  the  other,  a  ball  placed  in  the  middle  of  the  groove  will  roll 
down  with  accelerated  motion. 

By  combining  the  oscillatory  motion  across  the  groove  with  the  accelerated  motion  down  the  in¬ 
cline,  the  oscillatory  motion  may  be  made  to  trace  in  a  film  of  lycopodium  powder  equal  inter¬ 
vals  of  time  for  the  study  of  accelerated  motion. 

Grooved  Plank  complete  with  Sphere,  Releasing  Block  and  package  of  Lycopodium  Powder  .  .  .  6.26 


I 


102  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


Nos.  26-110  to  26-112  Nos.  26-161  and  26-166 


26-110  FALLING  BODY  APPARATUS,  retardation  to  free  fall  secured  by  INCLINED  PLANE  according 
to  Millikan  and  Gale’s  “A  First  Course  in  Physics,”  page  26,  for  determining  the  distance 
traversed  by  a  body  under  force  of  gravity  in  one,  two,  three,  or  four  seconds  under  uniformly 
accelerated  motion. 

The  apparatus  consists  of  a  clear,  straight-grained  wooden  plank,  16  feet  long,  with  accurately  cut 
V  groove  running  the  total  length,  which,  when  inclined  at  an  angle,  affords  an  inclined  plane  down 
which  a  steel  ball  may  roll  in  a  frictionless  path.  A  block  stop  for  this  ball  is  furnished  which 
may  be  clamped  to  the  plane  at  any  position  desired.  Time  interval  may  be  noted  by  any  conven¬ 
ient  means.  We  recommend  either  a  Seconds  Pendulum  No.  17-60,  or  a  Metronome  No.  17-120  $8.60 

26-112  - - ,  same  as  above,  but  8  feet  long.  This  is  to  be  used  in  connection  with  above  for  measuring 

velocity  acquired  per  second  by  a  body  under  force  of  gravity  in  uniformly  accelerated  motion  .  .  4.80 

26-120  FOUR-FOOT  FREE  FALL  DEMONSTRATION  APPARATUS  or  GUINEA  AND  FEATHER 
TUBE  for  demonstrating  that  all  bodies,  even  if  of  different  masses,  fall  in  equal  intervals  of  time 
if  released  from  friction  of  air  pressure. 

This  apparatus  consists  of  a  large  glass  tube,  one  end  sealed  air-tight,  the  other  end  with  a  brass  cup 

with  stop-cock,  bodies  of  different  masses  being  enclosed  previous  to  sealing .  6.76 

25- 140  THE  IMPROVED  ALL  METAL  FALLING  BODY  APPARATUS  (Ames  and  Bliss’  “A  Manual  of 

Experiments  in  Physics,”  Experiment  21),  for  determining  the  velocity  and  acceleration  of  a 
freely  falling  body. 

The  apparatus  consists  of  a  weighted  glass  plate  free  to  slide  in  a  vertical  metal  frame.  The  nickel- 
plated  support  rod  may  be  adjusted  to  accommodate  different  sizes  of  forks  and  the  clamp  adjusted 
to  vary  the  height  of  the  fork  on  the  rod. 

In  use,  the  plate  is  covered  with  an  even  layer  of  smoke  soot,  “Bon  Ami,”  or  whatever  is  desired 
to  give  it  a  tracing  surface.  A  fork  with  attached  stylus  is  fastened  in  the  clamp  and  adjusted  so 
that  the  stylus  will  mark  the  plate  as  it  is  allowed  to  drop  from  the  top  of  the  upright  frame. 

Price,  without  fork .  6.90 

TUNING  FORKS.  See  Section  61. 

26- 161  ACCELERATION  APPARATUS  for  determining  the  acceleration  of  a  freely-falling  body  moving 

with  uniformly  accelerated  motion. 

The  falling  body  is  a  metal  frame  to  which  a  heavy  glass  plate  is  held  by  spring  clamps.  This  metal 
frame  with  its  glass  plate  falls  before  an  electrically  driven  tuning  fork,  of  known  vibration  num¬ 
ber  and  which  may  be  moved  sideways  to  enable  one  plate  to  take  several  readings. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


103 


In  making  an  observation  the  plate  is  drawn  to  the  top  of  the  frame  and  fastened  by  a  thread.  The 
stylus  is  now  adjusted  to  touch  the  plate.  The  tuning  fork  is  set  in  vibration,  the  string  is  burned  in 
two  and  the  descending  plate  receives  a  fine  tracing  on  its  blackened  or  whitened  surface.  Meas¬ 
urements  are  taken  directly  from  the  plate  by  means  of  a  divider  or  scale.  Frequently  the  trac¬ 
ing  is  projected  on  a  screen  by  means  of  a  lantern. 

The  apparatus  may  be  used  as  an  Atwood’s  Machine  by  attaching  a  light  aluminum  wheel  on  ball¬ 
bearings  to  the  frame.  This  wheel  carries  a  cord  holding  the  falling  plate  on  one  end  and  the  coun¬ 
terbalancing  weights  on  the  other.  The  platform  and  ring  may  be  easily  attached  to  the  frame. 


Complete  without  Atwood’s  Attachment . $25.00 

25-166  ATWOOD’S  ATTACHMENT  for  use  with  No.  25-161  and  as  illustrated . 16.00 


Note.  —  The  glass  plate  of  Acceleration  Apparatus  No.  25-161  is  generally  coated  with  lamp-black  over  a  gas-jet  or  burning 
camphor.  A  much  more  cleanly  method  will  be  found  in  making  a  thin  paste  of  alcohol  and  whiting,  which  may  be  rapidly  ap¬ 
plied  to  the  plate  with  long  strokes  of  a  camel’s-hair  brush  or  a  soft  sponge. 


& 


No.  26-180 


25-180 


26-200 


25-201 
2  5-202 


FREE  FALL  APPARATUS  (Stewart  and  Gee’s  “Elements  of  Practical 
Physics,”  page  239),  for  finding  the  time  taken  by  a  body  falling  freely 
from  a  height,  and  in  determining  the  value  of  “g.” 

The  factors  in  determining  the  value  of  “g”  are  determined  by  the  free  fall 
of  a  steel  sphere  from  the  bronze-tipped  electro-magnet  at  the  end  of  a 
vertically  adjustable  brass  rod  to  a  slit  at  the  lower  end  of  a  pendulum  whose 
period  may  be  varied.  The  position  and  width  of  the  slit  is  adjusted  so 
that  the  sphere  dropping  vertically  passes  through  it  when  the  pendulum 
is  at  its  lowest  point.  The  electro-magnet  holding  the  sphere  and  the  one 
drawing  the  pendulum  aside  are  in  the  same  circuit,  which,  when  opened,  re¬ 
leases  both  simultaneously.  If  the  time  of  fall  equals  the  quarter  period 
of  the  pendulum,  the  sphere  passes  through  the  slit.  By  raising  or  lowering 
the  brass  rod,  this  equality  may  be  easily  produced.  One  jaw  is  covered  with 
lead,  in  order  that  the  experimenter  may  determine  by  ear  whether  the 
sphere  arrives  at  the  plane  of  the  slit  too  soon  or  too  late.  The  period  of 
the  pendulum  gives  the  time  of  the  fall.  The  distance  is  measured  from 
the  bottom  of  the  suspended  sphere  to  the  plane  of  the  slit. 

We  unhesitatingly  recommend  this  apparatus  for  very  accurate  determi¬ 
nations  of  “g” . $26.00 

UNIFORMLY  ACCELERATED  MOTION  APPARATUS  for  study  of  princi¬ 
ples  of  accelerated  motion  and  for  determination  of  factors  governing  a  body 
under  uniformly  accelerated  motion. 

The  apparatus  consists  of  a  car  which,  mounted  on  a  wire  inclined  at  a  slight 
angle,  is  free  to  move  down  the  incline.  The  wire  is  provided  with  a  hook  at 
one  end  and  a  turn-buckle  at  the  other  for  securing  taut  wire. 

Apparatus  complete  as  illustrated .  3.40 

LYON’S  CAR,  with  buffer .  1-96 

INCLINED-WIRE  OUTFIT,  including  screw,  hooks,  and  turn-buckle  with 
buffer  .  L45 


25-210  HALL’S  ACCELERATION  APPARATUS  according  to  Hall’s  “Elements 
of  Physics,”  Exercise  17,  page  508,  1912  edition.  Pendulum  Bar  with 
Counterpoise  and  Support  as  described . 


104 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PENDULUMS 


No.  26-230 


26-225  FOUR  BALL  PENDULUM  ILLUSTRATION  for  determining  factors  governing  the  laws  of  pendu¬ 
lums. 

The  apparatus  illustrated  must  not  be  confused  with  similar  designs  on  the  market,  as  it  will  be 


noted  that  our  instrument  will  support  in  adjustable  suspensions  four  pendulums. 

Pendulum  Clamp  with  four  balls  but  without  support . $1.95 

6-900  FOUR  PENDULUM  CLAMP  only  .  1.75 

Support  illustrated  is  No.  22-131  UNIVERSAL  STAND .  3.16 

26-227  THREE  BALL  PENDULUM  ILLUSTRATION,  same  as  above,  but  with  our  No.  6-902  Pendulum 
Clamp  for  holding  three  pendulums  m  adjustable  suspensions. 

Pendulum  Clamp  with  three  balls  but  without  support .  .90 

6-902  THREE  PENDULUM  CLAMP  only . 76 


25-230  PENDULUM  APPARATUS,  after  Turner  and  Hersey,  for  the  determination  of  the  Laws  of  the 
Pendulum. 

The  apparatus  consists  of  a  special  pendulum  clamp,  details  of  which  are  shown  in  illustration,  each 
designed  to  hold  two  pendulums.  For  different  masses,  we  list  three  bobs  of  different  metal;  for 
suspensions,  fine  wire. 

In  use,  the  pendulum  clamp  is  attached  by  means  of  an  iron  clamp  (our  No.  6-1160  Harcourt  Basic 
Clamp  “B”  being  shown  in  the  illustration)  to  a  convenient  support,  the  Cross  Beam  of  our 
Standard  Physics  Table  No.  1-100,  being  illustrated. 

Apparatus  complete  without  Basic  Clamp .  1.74 


SEPARATE  PARTS 

26-230a  PENDULUM  CLAMP  as  used  in  above . $0.64 

25-230b  SPECIAL  CYLINDRICAL  IRON  BOB . 25 

25- 230C  SPECIAL  CYLINDRICAL  LEAD  BOB . 30 

26- 230d  SPECIAL  CYLINDRICAL  BRASS  BOB . 30 

25- 230e  SPOOL  COPPER  WIRE,  No.  30 . 36 

6-1150  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “B” .  1.66 

26- 232  SIMPLE  AND  REVERSIBLE  PENDULUM  APPARATUS,  after  Hall  (No.  XLIV),  complete  with 

bobs  but  without  meter  stick .  1.96 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


105 


25-235  BI-FILAR  FOUR  PENDULUM  ILLUSTRATION  for  determining  factors  governing  the  Laws  of 
Pendulums. 

This  apparatus  consists  of  our  No.  5-906  Pendulum  Clamp  with  four  balls  of  equal  diameter.  These 
balls  are  attached  to  the  clamp  by  threads  of  lengths  to  obtain  vibration  periods,  as  1:  2:  3:  4. 
Pendulum  Clamp  with  four  balls,  but  without  illustrated  support . $2.95 

5-906  BI-FILAR  PENDULUM  CLAMP  only .  2.36 


Support  illustrated  is 

22-131  UNIVERSAL  STAND . '. . $3.15 

26-251  CULLER’S  ADJUSTABLE  LEVER,  PULLEY  AND  PENDULUM  CLASP  AND  HOOK  ROD 

after  Dr.  J.  A.  Culler,  Miami  University,  Oxford,  Ohio.  The  name  of  this  ingenious  device  is  de¬ 
scriptive  of  its  manifold  uses.  (See  Experiments  VII,  X  and  XI  of  Culler’s  “Laboratory  Manual 
of  Physics”.)  Clasp  and  Hook  Rod  only .  1.60 

25- 251A  - ,  with  Clamp . . .  2.40 

26- 260  REVERSIBLE  PENDULUM  for  determination  of  centers  of  suspension  and  oscillation,  and,  by 

measurement  of  the  distance  between  these  centers,  to  determine  the  length  of  the  equivalent 
simple  pendulum  and,  from  this,  the  value  of  the  acceleration  of  gravity. 

This  design  consists  of  a  nickel-plated  metal  rod  on  which  are  two  lens-shaped  bobs,  each  provided 
with  steel  knife-edges  with  the  edges  of  one  turned  towards  the  edges  of  the  other.  These  bobs 
may  be  adjusted  along  the  rod  as  desired,  thus  changing  the  centers  of  suspension  or  oscillation  at 
will.  The  pendulum  is  suspended  on  the  knife-edges  of  one  of  the  discs  on  the  bracket  and  stirrup, 
as  above  illustrated.  The  bobs  are  now  fixed  at  such  a  distance  apart  that  the  pendulum  vibrates 
with  the  same  period,  whether  it  is  suspended  from  knife-edges  of  one  bob  or  the  other,  —  the 
center  of  suspension  becoming  the  center  of  oscillation  when  the  pendulum  is  reversed.  The 
distance  then  between  the  knife-edges  is  the  length  of  an  equivalent  simple  pendulum. 

Reversible  Pendulum  complete  with  stirrup  and  bracket .  4.45 


io6 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


J. 


GRAVITY  AND  MOTION 


No.  25-310 


25-320 


25-310  SWIFTEST  DESCENT  APPARATUS,  comparing  descents  of  spheres  of  the  same  diameter  along 
inclines  of  different  curvatures. 

The  apparatus  consists  of  three  tracks  placed  on  an  incline  to  the  base  line,  —  one  track  describing 
a  cycloid  curve,  the  second  a  concave  circular  curve,  the  third  an  inclined  plane.  The  apparatus 
is  further  provided  with  a  device  for  the  simultaneous  start  of  all  three  spheres.  The  singular 
results  follow  a  simultaneous  start  of  all  three  spheres,  —  the  sphere  on  cycloidal  curve  reaches 
end  of  track  first,  on  concave  circular  track  second,  while  the  one  on  the  inclined  track  is  the 
slowest.  One  other  striking  experiment  will  be  noted,  —  no  matter  from  which  point  on  the 
cycloidal  track  the  sphere  is  started,  the  time  of  descent  to  the  end  of  the  track  will  always  be  the 


same. 

Complete  with  three  steel  spheres . $21.25 

26-320  DOUBLE  CONE  AND  PLANE  for  illustrating  the  seemingly  paradoxical  phenomenon  of  a  cone 
moving  up  an  incline,  which  is  of  such  shape  that  its  axis  actually  descends. 

Complete  as  illustrated,  of  finely  grained  and  neatly  polished  wood .  1.16 


No.  26-330 


25-330  CENTRIFUGAL  RAILWAY,  illustrating  the  opposition  offered  by  a  moving  body  to  any  influence 
exerted  to  counteract  its  tendency  to  move  in  a  straight  line. 

This  apparatus  consists  of  a  looped  circular  railway  down  which  a  body  may  roll  unobstructed.  At 
one  point  in  the  loop  illustrated,  the  body  is  held  by  centrifugal  force  against  the  under  side  of  the 
track  in  opposition  to  the  force  of  gravity. 

Complete  as  illustrated  with  car . 


$17.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


107 


26-10  UNIVERSAL  WAVE  MOTION  APPARATUS,  modification  of  Powell’s  and  Snell’s  designs,  combin¬ 
ing  features  of  both  into  one  instrument  capable  of  demonstrating  all  principles  of  each.  Thus 
the  combination  transverse  and  longitudinal  component  illustrating  waves  on  surface  of  a  liquid, 
wave  motion  as  set  up  by  transverse  displacements,  and  wave  motion  as  set  up  by  longitudinal 
displacements  are  all  strikingly  shown. 

WATER  WAVES.  In  our  model  we  show  that  the  particle  or  element  on  the  crest  moves  forward,  in 
the  trough  backward,  and  in  the  intermediate  positions  both  vertically  and  horizontally.  The 
elliptical  or  circular  orbits  of  the  disturbed  particles  are  ample  in  size  that  they  may  be  readily 
observed  by  all  even  in  the  largest  lecture  hall.  It  may  also  be  shown  that  the  wave  form  is  not  a 
sine  curve. 

TRANSVERSE  WAVE  FORM.  The  demonstration  of  movement  of  a  particle  transversely  and  the 
transverse  wave  form  as  well  as  the  analysis  of  the  resultant  sine  curve  is  especially  adapted  to  this 
model. 

LONGITUDINAL  WAVE  FORM.  Our  model  is  so  designed  that  in  demonstrating  any  of  the  above 
forms  the  condensations  and  rarefactions  set  up  by  longitudinal  vibrations  will  also  be  formed,  thus 
affording  a  striking  comparison  of  wave  forms. 

This  model  stands  about  three  feet  high  and  all  parts  are  so  proportioned  that  it  is  especially  adapted 
for  lecture  purposes.  The  elements  are  represented  by  balls;  vibrations,  transverse  or  longitudinal, 
are  communicated  by  brass  rods;  and  the  vibrations  are  set  up  in  the  rods  by  means  of  peculiarly 
cam-shaped  castings  eccentrically  mounted,  each  rod  to  its  own  casting,  and  all  on  a  shaft  operated 
by  a  single  crank.  When  the  rectangular  guide  frame  “A”  is  in  the  position  illustrated  both  trans¬ 
verse  and  longitudinal  wave  motions  are  demonstrated.  With  “A”  in  position  as  indicated  by 
dotted  lines  water  waves  and  longitudinal  waves  are  demonstrated. 

This  apparatus  is  carefully  assembled  and  all  parts  accurately  made.  All  woodwork  is  neatly  finished 
and  the  whole  presents  a  scientific  and  handsome  appearance . 


$66.00 


io8 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


26-20  WAVE  APPARATUS  for  illustrating  the  formation  of  transverse  and 
longitudinal  waves. 

This  model  consists  of  a  steel  ribbon  along  which,  at  regular  intervals, 
are  securely  fixed  cross  heads  bearing  at  either  end  a  metal  ball,  rod 
and  balls  on  either  side  of  the  ribbon  being  painted  a  distinguishable 
color  that  various  wave  forms  may  be  easily  differentiated.  This  steel 
ribbon  in  use  is  firmly  fixed  to  the  ceiling  by  means  of  the  heavy 
screw-eye  furnished  with  the  apparatus.  By  giving  lowest  the  cross¬ 
bar  a  motion  at  right  angles  to  the  steel  ribbon  a  motion  is  communi¬ 
cated  to  each  cross-bar  in'  turn,  illustrating  transmission  or  propa¬ 
gation  of  transverse  waves.  Longitudinal  waves  are  propagated  in 
similar  manner  by  depressing  one  end  of  the  lowest  cross-bar  in  a 
vertical  direction,  the  motion  thus  being  communicated  throughout 
the  entire  length. 

The  use  of  this  wave  model  fully  warrants  the  expense,  as  results 
obtained  are  entirely  satisfactory  and  may  be  seen  from  the  rear  of 
the  largest  lecture  hall.  The  model  is  about  13  feet  long,  with  cross¬ 
bar  attached  every  five  inches . $11.60 

/ 


No.  26-29 


26-29  SPIRAL  SPRING  for  illustrating  wave  motion,  either  transverse  or 
longitudinal. 

This  spring  is  constructed  of  spring  brass  wire  coiled  in  the  form  of  a 


spiral  .  $1.26 

26-32  RUBBER  CORD  for  illustrating  wave  motion .  .66 


No.  26—40 

26-40  METAL-FRAMED  WAVE  TROUGH  for  illustration  of  water  waves.  The  plate  glass  sides  of  this 
trough  are  supported  by  and  sealed  to  the  end  metal  castings  and  metal  base  to  form  a  trough  10 
inches  deep  by  5  feet  long.  The  water  level  line  is  accurately  parallel  to  the  base.  Waves  are  set 
in  motion  by  means  of  the  paddle  illustrated. 

This  trough,  framed  of  metal,  is  vastly  superior  to  designs  framed  of  wood,  in  that  possibility  of 
warping  and,  therefore,  leakage,  is  entirely  obviated.  It  is  much  more  substantial  and  the  metal 
offers  a  surface  for  a  durable  and  handsome  japanned  finish. 


Complete,  with  paddle 


$14.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


109 


SIMPLE  MACHINES 


LEVERS,  PULLEYS,  WHEEL  AND  AXLE,  INCLINED  PLANE, 

WEDGE,  SCREW 


No.  27-30 


27-10 


No.  27-46 


27-11 

27-12 

16-300 

27-30 


27-46 


27-60 


27-61 
27-61 a 
27-61 b 
27-62 
27-67 
27-76 

27-60 

27-96 


No.  27-46  (Showing  Lever  of  the  First  Class) 

COEFFICIENT  OF  FRICTION  APPARATUS  for  the 

study  and  determination  of  the  Coefficient  of  Friction. 

The  apparatus  consists  of  a  carefully  planed  white  wood 
strip,  50  X  20  centimeters.  The  friction  between  this 
surface  and  the  face  of  a  wood  block,  7.5  centimeters 
square,  is  determined  by  means  of  a  Spring  Balance. 

With  Spring  Balance . $1.37 

WHITE  WOOD  STRIP,  50  X  20  centimeters . 

WOODEN  BLOCK,  7.5  centimeters  square . 

SPRING  BALANCE,  250  grams  and  8  ounces . 

DEMONSTRATION  LEVER,  illustrating  simple  balances  and  also  for  experimental  use  as  a  lever 
of  the  first,  second,  or  third  class. 

Complete  apparatus  as  illustrated,  including  pointer,  two  of  No.  27-46  and  central  knife-edge  but 

without  Meter  Stick . .  . 

KITTREDGE  LEVER  CLAMPS  for  use  with  an  ordinary  Meter  Stick  in  determining  the  Mechani¬ 
cal  Advantage  of  a  Lever. 

This  clamp  is  made  up  of  two  metal  stampings  riveted  together  to  form  of  meter  stick  and  which  may 
be  clamped  to  it  by  means  of  a  thumb  screw.  A  knife-edge  protruding  on  each  side  offers  a  friction¬ 
less  support  for  the  loops  of  a  stirrup  for  attaching  weights  or  hook  of  the  scale  pan.  Per  set  of  Three 
LEVER  APPARATUS  for  the  study  of  Mechanical  Advantages  of  a  Lever. 

The  apparatus  consists  of  a  wooden  bar  to  which  is  attached  a  graduated  movable  cross  head  with 
metal  retaining  ends.  Complete  as  illustrated,  with  a  pair  of  scale  pans  with  improved  knife-edge 

bearings  after  Mr.  W.  E.  Rice . 

LEVER  AND  SUPPORTING  BAR  only . 

STRAIGHT  LEVER  . 

SUPPORTING  BAR  and  PIVOT . 

RICE  SCALE  PANS . . . Per  Pair 

SCALE  PANS,  ordinary  grade  with  attached  strings . Per  Pair 

RIDER  BLOCK,  after  Hall  and  Bergen  (Experiment  12),  for  use  on  meter  stick  in  determining  Weight 

of  Lever  Arms  . . 

U-SHAPED  WIRE  SUPPORTING  HOOK,  after  Turner  and  Hersey  (Experiment  M130)  .... 

COMPOUND  LEVER,  illustrating  a  combination  of  simple  levers  to  secure  power  equivalent  to  a 
simple  lever  with  long  arm. 

The  apparatus  consists  of  two  lacquered  brass  strips  connected  and  mounted  on  a  convenient  wooden 


base 


27-100  STEELYARD,  capacity  50  pounds . 

For  other  COMPOUND  LEVERS,  see  Section  29. 


$0.46 

.12 

.80 


1.74 


.60 


1.30 

.66 

.36 

.20 

.76 

.40 

.18 

.08 


4.60 

1.26 


no 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PULLEYS 

NEW  FORM  PULLEYS 


The  wheels  are  made  of  thin  pressed  steel,  5  centimeters  in  diameter.  Each  pulley  is  carefully  mounted  and 
having  less  bearing  surface  than  the  old  style,  turns  more  freely.  Designed  for  use  as  either  fixed  or  movable  pulley. 


27-126  SINGLE  PULLEY . $0.18 

27-126  DOUBLE  PULLEY . 30 

27-127  TRIPLE  PULLEY . 40 

27-128  QUADRUPLE  PULLEY . 55 


For  FRICTIONLESS  PULLEYS  we  recommend  the  following: 

HARCOURT  BALL-BEARING  FRICTIONLESS  PULLEYS 

A  PULLEY  is  one  of  the  most  essential  requisites  in  the  study  of  Mechanical  Powers.  The  attainment  of  results 
where  guesswork  is  not  required  for  the  formulation  of  the  laws  has  been  confined  largely  to  a  class  of  instruments 
not  within  the  reach  of  the  appropriation  of  many  educational  institutions.  In  many  of  the  pulley  experiments  as 
conducted  in  these  institutions  to-day,  the  student  cannot  be  blamed  for  the  inaccuracies  of  his  conclusions.  Our 
experience  has  advised  and  our  experimentation  has  designed  our  present  BALL-BEARING  FRICTIONLESS  PUL¬ 
LEY,  which  we  can  heartily  recommend.  It  has  the  further  quality  of  Expansion  Possibilities,  in  that,  with  a  basis 
of  the  single  unsheaved  pulley  and  with  the  addition  of  an  outfit  of  axles  and  stirrups,  any  combination  up  to  two 
pulleys  of  five  sheaves  is  possible. 


Illustrating  Unit  Parts  to  Assemble  as  Pictured  Opposite 


27-166  BALL-BEARING  PULLEY  UNIT  .  .  . 

27-167  AXLE  ROD,  Single  Pulley . 

27-169  AXLE  ROD,  Double  Pulley . 

27-171  AXLE  ROD,  Triple  Pulley . 

27-173  AXLE  ROD,  Quadruple  Pulley  .... 
27-176  AXLE  ROD,  Quintuple  Pulley  .  .  .  . 
27-177  STIRRUP,  Single,  Triple,  or  Quintuple 
27-179  STIRRUP,  Double  or  Quadruple  .  .  . 


$0.35 

.08 

.08 

.08 

.08 

.08 

.20 

.20 


Our  BALL-BEARING  FRICTIONLESS  PULLEY  is  shown  in  detail  in  the  above  illustration,  and  various 
sheaves  are  pictured  on  the  opposite  page. 

By  inspection  of  the  single  pulley  without  stirrup,  the  face  and  edge  of  which  are  both  shown,  it  will  be  noted 
that  this  pulley  is  made  up  of  two  parts,  each  stamped  out  of  one  piece  of  metal  by  means  of  expensive  tools  and  dies. 
Both  are  then  riveted  firmly  together  with  ball  race  in  place.  In  assembling  it  is  only  necessary  to  use  the  metal 
stirrup,  stamped  and  formed  also  by  tools  and  dies,  and  to  attach  to  pulley  by  means  of  the  shortest  axle  illustrated. 
No  tools  are  required,  as  all  attachment  is  secured  by  two  thumb  nuts.  In  assembling  a  sheave  of  two  or  four  pul¬ 
leys,  the  wider  stirrup  is  needed,  using  the  correct  length  axle  rod.  In  assembling  a  sheave  of  five  pulleys,  the  nar¬ 
row  stirrup  is  used  with  the  longest  axle  rod. 

Each  pulley  with  all  parts  is  neatly  nickeled  and  stirrup  is  provided  with  double  hooks.  For  convenience  in 
purchasing,  we  list  assembled  sheaves.  When  experimenting  with  these  pulleys,  we  desire  to  urge  upon  our  patrons 
the  necessity  of  using  a  cord  of  about  34  inch  diameter. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


hi 


No.  27-154 


No.  27-160 


No.  27-152 


27-160  SINGLE  BALL-BEARING  PULLEY,  comprises  one  No.  27-165,  one  No.  27-167,  one  No.  27-177  .  .  $0.60 
27-162  DOUBLE  BALL-BEARING  PULLEY,  comprises  two  No.  27-165,  one  No.  27-169,  one  No.  27-179  .  .95 
27-164  TRIPLE  BALL-BEARING  PULLEY,  comprises  three  No.  27-166,  one  No.  27-171,  one  No.  27-177  .  1.30 


No.  27-156  No.  27-158 


27-156  QUADRUPLE  BALL-BEARING  PULLEY,  comprises  four  No.  27-165,  one  No.  27-173,  one  No. 

27-179  . $1.66 

27-168  QUINTUPLE  BALL-BEARING  PULLEY,  comprises  five  No.  27-166,  one  No.  27-176,  one  No. 

27-177  .  2.00 


HARCOURT  STEEL  BALL-BEARING  PULLEY  ASSORTMENTS 


All  of  the  following  sets  are  made  up  of  the  well-known  Harcourt  Ball-Bearing  Pulleys  fully  illustrated  and  de¬ 
scribed  above.  Each  set  includes  pulleys,  stirrups,  and  axle  rods  sufficient  for  assembling  any  of  the  combina¬ 
tions  as  listed. 

27-140  SIMPLE  PULLEY  ASSORTMENT,  parts  sufficient  to  assemble,  —  4  Single  Pulleys  or  2  Double 

Pulleys . Per  Set  $3.00 

27-141  PULLEY  ASSORTMENT,  parts  sufficient  to  assemble,  —  6  Single  Pulleys  or  3  Double  Pulleys  or 

2  Triple  Pulleys . Per  Set  4.70 

27-142  PULLEY  ASSORTMENT,  parts  sufficient  to  assemble,  —  8  Single  Pulleys  or  4  Double  Pulleys 

or  2  Triple  Pulleys  or  2  Quadruple  Pulleys . Per  Set  6.40 

27-143  PULLEY  ASSORTMENT,  parts  sufficient  to  assemble,  —  12  Single  Pulleys  or  6  Double  Pulleys  or 

4  Triple  Pulleys  or  3  Quadruple  Pulleys  or  2  Quintuple  Pulleys . Per  Set  9.60 

The  above  assortment,  No.  27-143,  will  be  found  adequate  for  study  of  the  principal  combinations  of  pulleys 
in  deriving  mechanical  advantages  of  the  same.  It  is,  therefore,  highly  recommended  as  a  lecture-table  demonstra¬ 
tion  assortment. 

27-185  PULLEY  CORD,  especially  adapted  for  all  pulley  experiments.  This  cord  is  of  extra  quality 

hemp,  %  inch  diameter . Per  hank  of  5  yards  $0  20 


1 12 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  27-200 


No.  27-216 


No.  27-230a 


No.  27-230b 


No.  27-230C 


27-200 


27-201 

27-216 


LATHE  TURNED  PULLEY,  a  frictionless  running,  brass  pulley,  inches  in  diameter,  mounted 
in  heavy  brass  frame  on  hardened  steel  cone  bearings.  Each  pulley  is  carefully  turned,  centered 
in  a  lathe,  and,  therefore,  when  mounted  runs  absolutely  true  and  is  in  true  balance.  The  rim 
is  turned  with  square  groove  that  accurate  measurement  of  diameter  may  readily  be  secured.  Both 
ends  of  the  frame  are  provided  with  hooks  one  of  which  may  be  removed  from  the  frame  and  re¬ 
placed  by  any  rod  tapped  Y  X  20  (See  No.  6-10).  Different  combinations  as  illustrated  are 
possible  by  use  of  a  pair  of  steel  rods. 

All  parts  handsomely  nickel-plated . Each  Pulley 

STEEL  RODS  for  use  in  making  combinations'of  above  Lathe  Turned  Pulley . Per  Pair 

TRIPLE  TANDEM  PULLEY  for  comparison  of  the  mechanical  advantages  of  pulley  arrangement. 
Each  tandem  pulley  consists  of  three  pulley  wheels  of  different  diameters  fnounted  in  cone  bear¬ 
ings  in  a  metal  frame.  Each  pulley  is  lathe  turned,  carefully  mounted  and  adjusted  .  .  .Each 


$2.45 

.20 


1.05 


6-950  PULLEY  ON  ROD,  axis  at  right  angles  to  rod . . $0.94 

5-952  PULLEY  ON  ROD,  axis  in  same  plane  as  rod .  .90 

TACKLE  BLOCKS  (HARCOURT  PATENT).  These  commercial  pulleys  must  not  be  confused  with  inexpen¬ 
sive  types.  They  are  carefully  made  from  lignum-vitae  with  self-lubricating  iron  bushings.  Each  shell  is  provided 
with  a  swivel  hook  and  becket. 


27-230 


TACKLE  BLOCKS,  size  of  sheave  2 x/i  X  %  X  %  inches;  length  of  shell,  4  inches;  requires  rope  Y  inch 
diameter. 


Each 


a  b  c 

Single  Double  Triple 

$1.70  $2.10  $2.85 


We  are  prepared  to  furnish  the  commercial  blocks  of  cheaper  construction.  For  science  laboratory  use,  how¬ 
ever,  we  recommend  the  superior  quality  as  listed  above. 


27-235  MANILA  CORDAGE,  Yi  inch  diameter,  as  required  with  above  Tackle  Blocks.  This  rope  is  con¬ 
structed  of  only  the  best  quality  of  manila  hemp.  Sold  only  in  multiples  of  10  feet.  Per  10  Feet  $0.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


1 13 


No.  27-260  (Front  View) 


No.  27-260  (Top  View) 


No.  27-240  No.  27-242 

27-240  DIFFERENTIAL  PULLEY  HOIST,  for  illustration  of  and  determination  of  mechanical  advantage 
of  a  commercial  differential  pulley  hoist. 

This  hoist  is  carefully  made  and  thoroughly  tested  to  the  capacity  of  ton  before  shipping.  Only 
the  best  of  hand-made  chain  is  used,  and  careful  attention  to  all  details  makes  this  a  safe  instru¬ 
ment  under  full  capacity  and  of  an  accuracy  which  would  be  classed  under  Scientific  Apparatus. 
Regular  hoist,  6  feet;  minimum  distance  between  hooks,  17  inches;  weight,  22  pounds;  capac¬ 


ity,  ton;  chain  pull,  72  pounds  through  18  feet . $11.75 

27-242  DIFFERENTIAL  PULLEY  HOIST,  smaller  model  with  brass  pulleys,  mounted  on  stand .  7.60 


27-260  T-BEAM  UNIVERSAL  PULLEY.  This  pulley  is  one  of  our  Harcourt  Universal  T-Beam  Series, 
and  we  justly  claim  for  it  advantages  that  can  only  be  realized  when  once  used.  The  table  clamp 
is  our  No.  6-1000  Basic  Clamp  “A.”  Attached  adjustably  to  the  beveled  slide  of  this  clamp  is  our 
Universal  Pulley  Interlocking  Attachment  No.  6-1080.  This  attachment  consists  of  two  cast¬ 
ings,  the  interlocking  base  provided  with  a  nickel-plated  T-screw  for  fixing  to  the  beveled  slide 
top  of  the  basic  clamp,  and  a  pulley  arm  which  swivels  about  the  post  of  the  interlocking  base. 

As  may  be  noted,  this  arm  may  be  firmly  locked  by  the  T-screw  in  the  post.  At  the  end  of  the  pul¬ 
ley  arm,  cast  as  a  part  of  the  arm,  is  a  circular  block  in  which  are  drilled  a  number  of  holes,  in  any 
of  which  the  pulley  rod  may  be  locked  by  a  T-screw. 

The  pulley  itself  is  of  careful  construction  and  is  mounted  on  cone  bearings  in  a  stirrup  which  is 
attached  to  the  rod. 

We  claim  for  our  design  a  possibility  of  adjustments  never  heretofore  attained  by  any  design;  in 
addition,  a  greater  ease  and  rapidity  in  securing  multitudinous  positions.  We  also  secure  a  back¬ 
ward  and  forward  movement  along  the  beveled  slide.  All  positions  may  be  firmly  locked  by 
the  nickel-plated  T-screws. 

T-beam  Universal  Pulley,  complete  as  illustrated .  2.65 

Persons  equipped  with  Universal  T-beam  Basic  Clamp  “A”  need  purchase  only  Interlocking  Attachment. 

6-1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A”  .  .  $0.94 
6-1080  UNIVERSAL  PULLEY  INTERLOCKING  ATTACHMENT  .  .  .  1.76 


114 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  27-275 


27-275  PULLEY  DEMONSTRATION  APPARATUS.  The  frequent  call  for  a  complete  outfit  for  demon¬ 
stration  of  pulleys  and  the  application  of  the  principles  thereof  to  wheels  and  axles  and  capstans 
has  led  us  to  design  and  assemble  the  above  illustrated  combination. 

As  may  be  noted,  the  instrument  consists  of  two  upright  rods  mounted  on  our  new  form  H-base 
connecting  these  upright  rods  on  two  cross-bars  provided  with  special  clamps  for  attachment  to 
the  rods.  To  these  cross-bars  are  attached  the  various  combinations  which  can  be  assembled 
from  the  outfit  listed  below. 

The  apparatus  as  above  illustrated  is  furnished  complete  with  all  accessories  as  follows,  — 

A  Complete  Equipment  of  Pulleys  for  Illustrating: 

Fixed  pulley,  weight  and  power  equal. 

Fixed  and  movable  pulleys  for  securing  the  following  combinations:  weight  and  power 
as  1:2;  1:3;  1:4;  1:5;  1:6;  1:8;  and  1:10. 

These  pulleys  are  the  Harcourt  Steel  Ball-Bearing  Pulleys  (see  page  111),  an  outfit  being 
supplied  capable  of  giving  any  of  the  combinations  above  desired;  thus  one  may  secure 
quintuple,  quadruple,  triple,  double,  and  single  pulleys  in  various  combinations. 

Improved  Wheel  and  Axle,  5  diameters  which  are  based  upon  simple  weight  ratios. 

Capstan  and  Lever.  1  pair  triple  tandem  pulleys. 

The  equipment  which  we  furnish  consists  of  the  frame  itself,  the  Wheel  and  Axle,  the  Cap¬ 
stan  and  Lever,  a  pair  of  Triple  Tandem  Pulleys  and  in  addition,  a  sufficient  number  of 
the  Harcourt  Ball-bearing  Pulley  Units,  Axles  and  Stirrups  to  set  up  the  various  pulley  com¬ 
binations  shown  above. 


Apparatus  complete  as  described  without  weights 


$20.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


115 


PULLEY  STUDY  APPARATUS 


PULLEY  STUDY  APPARATUS 

25-251  CULLER’S  ADJUSTABLE  LEVER,  PULLEY  AND 
PENDULUM  CLASP  AND  HOOK  ROD  after 
Dr.  J.  A.  Culler,  Miami  University,  Oxford,  Ohio. 

The  title  of  this  ingenious  device  is  descriptive 
of  its  manifold  uses.  (See  Experiments  VII,  X  and 
XI  of  Culler’s  “Laboratory  Manual  of  Phys¬ 
ics.”)  Clasp  and  Hook  Rod  only . $1.60 


No.  27-335 


The  only  distinctive  item  required  for  “set  up”  illus¬ 
trated  is  as  follows: 

27-290  CAPSTAN  ARM  with  CAPSTAN.  This 

is  a  special  casting  with  clamp  and  arm 
in  one  piece.  At  the  end  is  mounted  a 
capstan .  $1.90 

Other  apparatus  illustrated,  elsewhere  listed. 

6-770  RIGHT  ANGLE  CLAMP . 95 

22-131  BASE  AND  ROD .  3.15 

6-645  HOOK  COLLARS  (4  needed)  .  .  Each  .24 

27-160  BALL-BEARING  SINGLE  PULLEYS  (4 

needed)  . 60 

27-162  BALL-BEARING  DOUBLE  PULLEY  .  .  .96 

27-326  WHEEL  AND  AXLE .  1.75 

5-10d  SUPPORT  ROD .  .25 

Note.  Our  No.  22—130  Tripod  Support  without  levelling  screws  may 
be  used  if  desired  in. the  place  of  the  one  illustrated. 


25-251a 


with  Clamp . $2.40 

27-306  WOODEN  STRIP  with  TWO  HOOKS  after  Turner  and  Hersey,  Exp.  M320  .20 


No.  27-326 


27-325  ALUMINUM  FIVE  DIAMETER  WHEEL  AND|AXLE,  for  attachment  to  sup¬ 
port  rod  by  means  of  a  clamp,  in  determining  the  Mechanical  Advantage 
of  a  Wheel  and  Axle. 

This  Wheel  and  Axle  is  made  from  new  specifications  which  have  been  figured 
on  the  basis  of  simple  ratios.  It  is  made  of  aluminum,  nicely  finished,  with 
5  diameters.  It  is  mounted  in  cone  pivots  in  a  metal  frame  attached  to  a 


Yl  inch  rod  for  use  in  clamp. 

Without  Clamp .  1.75 

The  Clamp  illustrated  is  No.  6-770  RIGHT  ANGLE  CLAMP . 95 


27-336  WHEEL  AND  AXLE,  after  Hall  and  Bergen’s  “A  Text-Book  of  Physics,”  para¬ 
graph  64,  for  determining  the  Mechanical  Advantage  of  Wheel  and  Axle; 
also  provided  with  attachments  showing  that  the  Wheel  and  Axle  is  simply 
a  modified  lever  of  the  First  Class. 

This  apparatus  consists  of  two  wooden  discs  combined  in  one  piece  attached  at  its 
center  to  a  wooden  rod  by  means  of  a  screw,  about  which  it  is  free  to  move 
as  an  axle.  This  wooden  rod  is  devised  for  clamping  to  the  cross  beam  of  the 
Standard  Physics  Table  or  other  convenient  means  of  support.  At  various 
points  on  the  disc  are  drilled  holes  to  which  cords  may  be  attached  by  use 
of  brass  pins  thrust  into  them .  .96 


Ii6  L.  E.  KNOTT  APPARATUS  CO,,  BOSTON 


No.  27-345  No.  27-360 


27-345  HORTVET’S  APPARATUS,  illustrating  that  the  Mechanical  Advantage  of  the  Wheel  and  Axle  is 
the  same  as  that  of  the  Lever  of  the  first  class;  also  for  demonstrating  principles  of  both  ma¬ 
chines  which  are  not  possible  with  the  simplified  apparatus. 

01 

This  apparatus  consists  of  an  upright  wooden  stand,  vertically  supported  on  which  is  a  disc  of  wood 
having  2  diameters.  At  various  convenient  points  on  this  disc  are  drilled  holes  into  which  brass 
pins  may  be  thrust  for  support  of  cords  which,  suspended  from  these  pins,  answer  the  double  purpose 
of  attaching  weights  and  of  supplying  a  plumb  line  for  measuring  the  diameters  of  the  two  discs  or  of 
lengths  of  the  “Power”  and  “Weight”  Arms,  the  readings  being  taken  from  the  plumb  line  dropped 
from  the  center  axle.  Just  below  the  disc,  attached  at  right  angles  to  the  upright,  is  a  cross  head 
which  bears  a  scale  and  a  narrow  mirror  which  obviates,  in  reading,  errors  due  to  parallax. 

Experimental  work  on  Levers,  with  fulcrum  below  or  above  line  of  support  of  “Power”  and  “Weight,” 
is  one  of  the  features  of  this  instrument  not  possible  on  instruments  of  simple  form.  Many  other 
interesting  problems  are  possible  with  this  apparatus. 

Apparatus  complete  as  illustrated  with  the  addition  of  a  simple  Lever  which  may  be  attached  in 
place  of  the  disc  on  the  upright . 

27-360  GAGE’S  MECHANICAL  POWERS  APPARATUS  for  determining  Mechanical  Advantage  of  simple 
machines  such  as  the  Lever  of  the  first,  second,  or  third  class,  the  Wheel  and  Axle,  and  the  Pulley. 

The  apparatus  consists  of  a  well-balanced  lever  arm  provided  with  a  brass  central  piece  with  holes 
through  which  may  be  thrust  the  fulcrum  pin  on  which  lever  may  be  supported  on  the  forked 
support  in  demonstrating  an  equal  arm  lever  of  the  first  class.  A  second  hole  provided  in  this 
brass  piece  serves  to  illustrate  the  effect  of  raising  or  lowering  the  center  of  oscillation.  The  illus¬ 
tration  shows  method  of  securing  levers  of  the  second  and  third  classes,  the  second  class  being  the 
one  illustrated. 

The  forked  stand  is  also  for  use  as  a  support  for  the  wheel  and  axle  (two  being  illustrated  above, 
but  one  only  being  furnished).  The  weight  is  supplied  by  means  of  special  forms  of  double-hooked 
brass  weights,  ten  of  which  are  furnished  with  each  outfit. 

Apparatus  complete  as  illustrated,  including  one  forked  stand,  one  lever  bar,  one  wheel  and  axle,  sup¬ 
port  rod  and  round  base,  one  clamp  and  arm,  one  ball-bearing  single  pulley,  one  stirrup,  a  scale 
pan,  and  ten  double-hooked  weights . 


$7.26 


7.65 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


117 


27-390 


27-392 


27-393 

27-394 

27-400 


27-402 

27-405 


27-410 


HALL’S  IMPROVED  INCLINED  PLANE  WITH  SIDE  RAILS  AND  SCREW  ADJUSTMENT. 

This  plane  is  a  neatly  finished  close-grained  wooden  plank  provided_ivith  side  ledges.  It  is  120 
centimeters  long  and  15  centimeters  wide.  It  is  furnished  with  screw  adjustment  for  comparison 
of  masses  by  the  acceleration  test.  (See  Hall  &  Bergen’s  “A  Text-Book  of  Physics,”  Exer¬ 
cise  36) . $1.60 

MAHOGANY  FINISHED  POLISHED  INCLINED  PLANE,  after  Millikan,  Gale  and  Bishop,  “Lab¬ 
oratory  Physics”  (Experiment  17).  This  plane  is  a  smooth  hardwood  surface,  5  inches  wide, 

4  feet  long .  .76 

PULLEY  IN  FRAME,  as  used  in  above,  for  attachment  to  any  board  . .  .  .76 

SONOMETER  ATTACHMENT  for  Inclined  Plane  No.  27-392  . 20 


HALL’S  INCLINED  PLANE  APPARATUS  for  determining  the  mechanical  advantage  of  the 
inclined  plane. 

This  apparatus  consists  of  a  wooden  base  to  which  is  hinged  a  board,  the  surface  of  which  is  carefully 


smoothed  and  finished.  This  board  may  be  inclined  at  any  desired  angle  as  indicated  by  the  grad¬ 
uated  metal  arc,  and  set  to  same  by  means  of  a  knurled  head.  “Power”  and  “weight”  are  balanced 
over  a  freely  running  pulley  set  in  pivotal  bearings.  Graduated  scales  for  both  incline  and  height. 

Plane  only,  without  illustrated  scale  pan,  roller,  and  weights .  4.45 

- ,  same  as  above  but  is  provided  with  a  roller  as  above  illustrated,  adjusted  to  weigh  exactly 

one  pound.  It  is  also  furnished  with  the  scale  pan  but  without  weights .  6.60 

ROLLER  FOR  INCLINED  PLANE  for  use  as  the  “Weight”  in  determining  the  Mechanical  Ad- 


No.  27-410 


vantage  of  the  Inclined  Plane. 

Consists  of  a  carefully  turned  roller,  ends  centered  and  pivoted  in  metal  frame  . 

PRATT  INSTITUTE  INCLINED  PLANE  for  determining  mechanical  advan¬ 
tage  of  an  inclined  plane. 

This  apparatus,  manufactured  by  us,  consists  of  two  hinged  boards  of  close- 
grained  hardwood,  the  upper  surface  of  which  is  carefully  planed  and  finished 
smooth.  The  variable  inclines  are  secured  by  means  of  the  swiveled  brass 
rods  which  may  be  locked  in  any  position  desired.  “Power”  and  “weight” 
are  balanced  over  a  ball-bearing  single  pulley  on  rod,  adjustably  mounted 
in  a  special  bracket  casting.  For  the  “power”  it  is 
designed  that  the  roller  illustrated  above  and  weigh¬ 
ing  11  pounds  be  used;  for  “weight,” 
hanger  and  weights  illustrated  and 
described  in  Section  16. 

Inclined  Plane  only,  without  illustrated 
weights,  hanger,  or  roller  .  .  $7.35 


1.95 


27-412  PRATT  INSTITUTE  INCLINED  PLANE  ROLLER.  This  roller  as  above  described  weighs  11 
pounds.  The  surface  is  carefully  turned  and  is  mounted  in  a  frame  in  pivotal  bearings.  Although 
designed  especially  for  use  with  the  above  inclined  plane  it  may  be  used  to  advantage  on  any  incline 
whatsoever. 

Roller  only,  as  above  illustrated . 

WEIGHTS.  Section  16. 


$3.15 


n8 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


• » 


27-420  WEINHOLD’S  DEMONSTRATION  INCLINED  PLANE  for  the  quantitative  study  of  factors 

governing  mechanical  advantage  of  an  inclined  plane. 

In  this  apparatus,  with  graduated  arc,  length,  height,  and  incline  dimensions,  not  only  may  the 
Mechanical  Advantage  of  an  Incline  be  quantitatively  determined,  but  also  the  normal  pressure 
on  the  plane  can  be  measured. 

The  apparatus  consists  of  a  frame,  as  illustrated,  similar  in  appearance  to  any  carefully  constructed 
Inclined  Plane.  The  roll,  however,  of  this  plane  is  provided  with  three  stirrups  for  use  as  illus¬ 
trated  in  measuring  normal  pressure  on  the  plane,  one  component  being  determined  by  a  mass 
hung  over  a  pulley  attached  to  the  upright  rod  at  the  right,  the  other  component,  by  the  mass 
hung  similarly  at  the  left. 

This  plane  is  carefully  constructed  throughout,  all  parts  being  neatly  finished. 

Furnished  complete  as  illustrated,  but  without  weights  of  any  kind . Duty  Free  $28.45 


No.  27-436 


27-435  INCLINED  PLANE  CAR  for  use  with  weights  as  the  “Weight”  in  determining  the  Mechanical 
Advantage  of  the  Inclined  Plane. 

In  this  car  we  have  attempted  to  obviate  the  errors  of  the  ordinary  four-wheel  type,  and  use  a  car 
with  three  wheels  only,  thus  securing  positive  wheel  action  on  all  three  wheels. 

The  body  of  this  car  is  a  metal  casting,  neatly  finished  in  japan;  the  wheels,  mounted  in  frictionless 


cone  bearings,  are  lacquered  brass.  A  hook  for  attaching  the  power  is  also  provided . $1.55 

27-440  INCLINED  PLANE  CAR,  type  with  four  wheels  in  pivotal  bearings .  1.10 

27-450  WOODEN  SPREADER  for  experiments  with  an  Inclined  Plane  when  it  is  desired  to  use  “Power” 
parallel  to  base. 

When  there  is  no  slot  lengthwise  of  the  incline,  this  spreader  will  be  found  a  great  convenience  .  .  .10 

27—465  RUBBER  CORD  for  use  in  experiments  with  an  Inclined  Plane  Car  on  Inclined  Plane  in  Inertia 

Experiments,  as  described  in  Hall  &  Bergen’s  “A  Text-Book  of  Physics,”  Exercise  36  .  .  Each  .20 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


119 


27-475 


MODEL  OF  WEDGE  for  determining  the  Mechanical 
Advantage  of  a  Wedge. 

This  apparatus  consists  of  a  wedge-shaped  metal  skel¬ 
eton  which  in  operation  is  held  between  three  easily 
running  pulley  wheels  supported  above  and  below 
the  wedge.  “Power”  is  attached  by  means  of  a 
cord  over  the  fourth  pulley  illustrated.  “Weight”  is 
supported  from  above  on  hinged  platform. 

Complete  without  weights . 

WEIGHTS.  See  Section  16. 


27-485  WEDGE,  consisting  of  a  two-part  piece  of  hard  wood,  18  centimeters  long,  each  part  2 Y2  centimeters 

at  point  of  greatest  thickness . Each  $0.80 


No.  27-610  No.  27-520 


27-500  MODEL  OF  A  SCREW  for  the  qualitative  illustration  of  the  great  force  of  a  screw.  The  design 
above  pictured  illustrates  the  tremendous  power  that  may  be  secured  by  means  of  a  screw. 

This  design  consists  of  a  modification  of  one  of  our  T-Beam  designs,  the  modification  consisting  of 
a  special  casting  attachment  with  breaking  wedges  securely  fastened  to  the  face  of  our  Basic 

Clamp  “B”  . $1.65 

27-510  JACK  SCREW,  demonstrating  the  Mechanical  Advantage  of  the  Screw;  also  used  for  leveling  up 


purposes. 

This  Jack  Screw  is  1  inches  in  diameter  at  the  base  and  has  a  range  from  2 %  to  3Y%  inches.  By 
use  of  extension  bases  B  and  C,  a  range  of  from  2J£  to  6 l/i  inches  is  possible.  An  auxiliary  pointed 
screw  D  is  supplied  which  may  be  used  in  place  of  the  screw  with  swivel  cap  when  desired.  The 
base  E  is  also  provided  for  use  in  special  cases. 

Jack  Screw  complete  as  illustrated,  including  A,  B,  C,  D,  and  E .  1.85 

27-510A  JACK,  only .  1.00 

27-610B  EXTENSION  BASE,  2  inches  high . 30 

27-510C  EXTENSION  BASE,  1  inch  high . 20 

27-610D  EXTENSION  SCREW . 20 

27-610E  EXTENSION  BASE . 20 

27-520  FIVE-TON  ROLLER-BEARING  JACK  SCREW.  These  Jack  Screws  are  of  cast  iron  with  a  1  % 
inch  steel  screw  with  square  threads  and  provided  with  roller  bearings.  Total  height  when  screw 
is  closed  is  approximately  8  inches;  lifting  capacity  five  tons .  4.30 


120 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


MODELS  OF  COMPLEX  MACHINES 

28-10  SIMPLE  GEARED  WHEELS,  illustrating  the  great  mechanical  advantage  of  a  system  of  geared 

wheels. 

This  system  consists  of  two  wheels  with  pinions  one-fourth  the  diameter  of  the  wheels,  while  a  third 
wheel  has  a  drum  of  the  same  ratio,  thus  giving  a  mechanical  advantage  of  1  to  64.  Gears  mounted 
on  rod  for  clamping  to  a  support.  Apparatus  as  illustrated  shows  use  of  our  No.  6-770  Right 
Angle  Clamp  mounted  on  the  rod  of  our  No.  22-130  Universal  Support. 


Geared  wheels  only,  without  illustrated  clamp . .  $3.86 

The  clamp  illustrated  is  6-770  Right  Angle  Clamp .  .96 


28-26  ENDLESS  SCREW  for  determining  the  mechanical  advantage  of  a  gear  operated  by  a  screw. 

This  apparatus  consists  of  a  disc  gear  with  drum  for  holding  weight.  This  gear  is  actuated  by  an 
endless  screw,  one  end  of  which  terminates  in  a  drum  around  which  is  attached  the  “power.”  The 
whole  is  mounted  to  a  casting  which  is  attached  to  a  rod  by  a  swivel  joint  which  may  be  held  fixed 
by  a  thumb  nut.  This  rod  may  be  clamped  to  any  support  by  use  of  any  right  angle  clamp,  our 


No.  6-770  Clamp  being  illustrated. 

Endless  screw  only,  without  illustrated  clamp .  6.46 

The  clamp  illustrated  is  6-770  Right  Angle  Clamp . 96 


28-76  CRANE  DEMONSTRATION  APPARATUS  for  quantitative  demonstrations  of  boom  stress  and 

guy  strains  in  cranes. 

This  apparatus  consists  of  a  boom  devised  to  register  all  stresses  in  pounds  or  grams  up  to  30  pounds 
or  16  kilograms.  It  is  shown  illustrated  with  apparatus  previously  listed  which,  if  already  a  part  of 
the  school  equipment,  need  not  be  added. 

Crane  Boom  only,  with  attached  chains  . . $6.60 

28-78  THREADED  HOOK,  threaded  X  20,  for  use  with  No.  6-786  Right  Angle  Clamp  as  illustrated  .16 

16-332  SPRING  DYNAMOMETER,  registering  20  pounds . .  2.16 

Other  apparatus  above  illustrated  but  previously  listed  is  as  follows: 

6-1160  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “B” .  1.66 

6-730  RIGHT  ANGLE  CLAMP . 66 

6-785  RIGHT  ANGLE  CLAMP . 46 

6-20e  SUPPORT  ROD,  19  millimeters  diameter,  100  centimeters  long .  1.00 

28-79  CRANE  BOOM  after  Fuller  and  Brownlee  (Experiment  24) .  .26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


121 


PRATT  INSTITUTE  APPLIED  PHYSICS 

APPARATUS 


On  the  following  pages  is  illustrated  a  line  of  apparatus  as  new’  to  the  scientific  instrument 
houses  as  it  is  to  educational  laboratories  in  America.  This  line  follows  the  designs  as  used  in  Pratt 
Institute,  which  have  been  worked  out  to  meet  the  definite  need  of  such  work  as  is  done  at  this 
institution. 

The  illustrations  showing  the  line  we  are  now  offering  were  made  from  the  pieces  built  for 
Wentworth  Institute,  Boston,  under  the  immediate  supervision  of  Professor  W.  H.  Timbie,  Director 
of  the  Applied  Physics  Department. 

Technical  Schools,  Trade  Schools,  Manual  Training  Schools,  and  High  Schools  giving  voca¬ 
tional  or  manual  training  courses,  will  be  interested  in  these  pages. 

» 

•  DISTINCTIVE  FEATURES.  While  some  of  the  pieces  in  form,  at  least,  will  suggest  the  older 
types  common  in  laboratory  work,  it  must  be  noted  that  there  is  an  essential  difference,  viz.,  size. 
All  the  parts  are  made  large  for  a  definite,  pedagogical  reason,  the  educational  value  of  muscular 
reaction  serving  as  the  keynote  of  this  work  in  Applied  Mechanics. 

The  large  crane,  for  example,  will  illustrate  our  point.  This  stands  over  seven  feet  high  and 
is  capable  of  handling  a  load  of  over  200  lbs.  It  at  once  impresses  the  student  with  its  commercial 
importance  and  hence  worthy  of  his  serious  attention.  The  design  is  such  that  notwithstanding 
that  the  commercial  form  has  been  maintained  every  strain  and  reaction  may  be  definitely  de¬ 
termined  and  correct  functions  deduced. 


No.  27-410 


27-410  INCLINED  PLANE.  This  instrument,  when  used  in  connection  with  the  11-lb.  roller  as  illustrated, 
is  well  worked  out  for  the  study  of,— 

1st,  Forces  supporting  a  body  on  a  frictionless  surface. 

2d,  When  used  in  connection  with  the  Pratt  Institute  car,  catalogue  No.  27-435,  a  study 
of  the  forces  parallel  to  the  incline  may  be  made. 

3d,  When  used  with  a  friction  block,  catalogue  No.  27-12,  the  determination  of  the  coef- 
cient  of  friction  by  the  two  more  common  methods  is  readily  made. 

By  the  use  of  this  plane  all  of  the  above  problems  may  be  solved  in  a  more  effective  way,  than  with 
the  plane  usually  furnished. 

Inclined  Plane  as  listed,  without  weights,  hanger,  and  roller . $7.35 


27-412  ROLLER,  accurately  centered  and  finished,  weight  11  lbs .  3.16 

27-435  PRATT  INSTITUTE  CAR  of  accurate  construction  and  correct  design .  1.65 

HANGERS  AND  WEIGHTS.  Section  16. 


122 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


29  30  SHEAR  LEGS.  A  most  impressive  illustration  of  the  composition  of  forces  as  applied  to  the  shear 
legs,  solving  definitely  the  following: 

1st.  The  tension  in  the  tie. 

2d.  The  compression  in  the  legs  of  shears. 

3d.  The  forces  necessary  to  keep  the  legs  from  spreading. 

Made  of  seamless  tubing,  correct  design  of  hinge  so  that  every  force  is  exerted  at  its  proper  point. 
Price  complete,  without  balances,  weights,  or  hanger . 

15-334  SPRING  DYNAMOMETER,  registering  60  pounds  ......... 

HANGERS  AND  WEIGHTS.  Section  16. 


$5.40 

3.20 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


123 


No.  29-60 


29-60  SIMPLE  TRUSS.  This  simple 
apparatus  serves  to  teach  in  the 
most  direct  manner  possible, 
forces  in  the  Simple  Stick  and 
Tie.  The  angle  of  inclination 
and  load  may  be  varied  at  will 
and  the  component  forces  at 
each  angle  accurately  deter¬ 
mined.  When  the  angle  of  the 
Truss  is  increased  to  90  degrees, 
the  problem  is  even  more  inter¬ 
esting  to  the  student. 

Price,  without  Balances  and 

Weights . $2.86 

29-80  SMALL  HOISTING  CRANE.  A 

substantial,  but  simply  designed 
apparatus  for  determining  both 
the  tension  and  compression  in 
the  Hoisting  Crane.  In  this  ex¬ 
ercise  the  weight  of  the  boom, 
which  is  material,  should  be 
taken  into  consideration. 

Price,  without  Balances  and 


Weights .  3.85 

16-332  SPRING  DYNAMOMETER, 

registering  20  pounds .  2.15 


No.  29-100 


29-100  ROOF  TRUSS.  The  laws  of  Equilibrium,  as  manifest  in  the  simple  Roof  Truss,  are  strikingly  solved 
with  the  above  apparatus.  Note  that  the  pressure  at  every  point  is  definitely  measured.  The 
support  for  holding  the  Truss  against  the  side  of  the  wall  is  so  designed  that  the  Truss  may  be 
loaded  with  a  block  of  iron  of  uniform  size,  resembling  pressure  or  strains  made  by  the  snow  load 
or  the  wind  pressure  load  on  the  roof. 

Price  of  parts  complete  as  illustrated,  without  Balance,  Weights  and  Hangers . $4.25 

16-334  SPRING  DYNAMOMETER,  registering  60  pounds .  3.20 

HANGERS  AND  WEIGHTS.  Section  16. 


124 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


• » 


DAVIS’  MODEL  BRIDGE 


DESIGNED  BY 

Prof.  HARVEY  N.  DAVIS,  Harvard  University,  Cambridge,  Mass. 


No.  29-110 

29-110  DAVIS’  MODEL  BRIDGE  for  the  study  of  reactions  in  a  bridge  truss.  As  all  members  are  inter¬ 
changeable,  this  model  will  serve  to  set  up  and  demonstrate  the  reactions  in  a  Simple  Truss,  a 
Four-Panel  Pratt  Truss,  a  Five-Panel  Pratt  Truss,  a  King  Post  Truss,  Underslung  King  Post 
Truss,  a  Cantilever  Truss,  etc. 

This  apparatus  is  composed  of  members  of  aluminum  and  mahogany  strips  and  tubes  of  aluminum. 

The  model  as  illustrated  is  7  feet  long,  25  inches  high,  supported  on  piers  designed  for  convenient 
use.  The  test  member  is  of  solid  mahogany,  provided  with  special  cast  bronze  attachments  for 
clamping  to  the  pins  and  holding  the  dynamometers  when  measuring  tensions  or  compressions  of 
any  of  the  members. 

Complete  as  illustrated,  with  piers,  tension  and  compression  members,  test  member,  and  with  special 

attachment  for  holding  the  weight  hanger,  but  without  weight  hanger,  weights  or  dynamometer  $38.00 

Upon  request  we  will  send  free  a  pamphlet  containing  a  series  of  laboratory  experi¬ 
ments  and  exercises  carefully  prepared  by  Professors  Davis  and  Black.  Addi¬ 
tional  copies  for  students’  use  furnished  at  a  nominal  price. 

WEIGHTS  and  WEIGHT  HANGERS.  See  Section  16. 

DYNAMOMETERS.  See  Section  16. 

LARGE  HOISTING  CRANE  OR  DERRICK 

(For  illustration,  see  following  page) 

29-125  LARGE  HOISTING  CRANE  OR  DERRICK.  The  cut  will  show  at  a  glance  the  method  of  determin¬ 
ing  the  various  forces,  such  as: 

1st.  The  tension  in  the  tie. 

2d.  The  vertical  and  horizontal  forces  exerted  by  a  boom  against  the  mast. 

3d.  The  amount  and  direction  of  the  total  force  of  the  boom  against  the  mast. 

4th  The  tension  in  each  guy  rope. 

5th  The  vertical  and  horizontal  floor  reactions  at  the  foot  of  the  mast. 

6th.  The  horizontal  component  of  the  forces  in  the  guy  ropes.  Compare  this  with  the 


horizontal  reaction  at  the  foot  of  the  mast. 

Complete  without  Platform  Scale,  Balances,  and  Weights . $18.75 

29-130  PLATFORM  SCALE,  as  illustrated  opposite .  18.76 

16-334  SPRING  DYNAMOMETER,  registering  60  pounds .  3.20 

HANGERS  AND  WEIGHTS.  Section  16. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


125 


LARGE  HOISTING  CRANE  OR  DERRICK 


See  description  on  preceding  page 


126 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  29-135 


29-135  FORCES  IN  A  UNIFORM  METAL  BAR  3  FEET 
LONG  WITH  SLIDING  LOAD.  With  this  ap¬ 
paratus  the  forces  acting  on  a  body  supported  by 
two  cords  not  parallel,  also  by  two  cords  parallel, 
may  be  definitely  worked  out.  Without  knife- 
edge  clamp . $7.50 


No.  29-145 


5-696  KNIFE-EDGE  CLAMP,  as  illustrated  in  above . $0.55 

29-145  STEELYARD  OF  LARGE  LABORATORY  FORM.  The  apparatus  is  made  from  a  uniform  bar  with 
measurable  counterpoises  and  sliding  weights.  The  apparatus  is  designed  to  be  calibrated  by  the 
student  according  to  the  principles  evolved  in  determining  the  center  of  mass  in  Uniform  Bar 


Experiments.  Without  weights  and  hanger  and  without  support .  9.60 

22-130  UNIVERSAL  STAND,  suggested  as  a  support  for  above  outfit .  2.10 

5- 16a  CROSS  BAR  SUPPORTING  ROD,  as  illustrated  above .  .25 

6- 730  RIGHT  ANGLE  CLAMP,  as  illustrated  above . 66 


No.  29-150 


29-150  COMPOUND  LEVER  AND  JACK  SCREW.  Large  in  size  and  substantially  built.  An  apparatus 
for  use  on  the  lecture  desk  or  in  the  laboratory,  in  determining  the  mechanical  advantage  of  the 
Compound  Lever  and  Jack  Screw. 

Consists  of  a  substantial  base  with  metal  uprights  on  which  are  attached  the  nickel-plated  steel 
members  of  the  Compound  Lever.  The  Jack  Screw  is  of  the  commercial  type,  accurately  cut 
screws  and  substantially  built. 

Without  Weights,  Weight  Hanger  and  Dynamometer . $14.75 

15-332  TWENTY-POUND  DYNAMOMETER,  20  pounds  by  pound,  as  illustrated  above  in  outline  .  2.15 

WEIGHTS  AND  WEIGHT  HANGERS.  See  Section  16. 

29-166  WORKING  MODEL  OF  THE  ARCH.  A  four-foot  model  so  designed  that  all  the  reactions  and 
thrusts  may  be  definitely  determined. 

1.  The  vertical  reaction  at  the  abutments. 

2.  The  horizontal  reaction  at  the  abutments. 

3.  The  horizontal  force  at  the  center  of  the  arch  ring. 

Complete  without  Balances  and  Weights 


29.75 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


127 


No.  29-166 


29-166  SCREW  JACK  WITH  WHEEL,  BASE,  AND  BAR.  The  efficiency  test-uf  the  commercial  screw 
jack  has  heretofore  been  considered  out  of  the  realm  of  laboratory  work,  even  in  technical  schools. 
The  use  of  adequate  load  to  represent  real  conditions  has  not  been  feasible  except  by  this  method 
found  so  successful  in  Pratt  Institute. 

With  the  apparatus  the  working  load  may  be  reckoned  in  terms  of  tons,  while  the  power  is  in  terms 

of  hundreds  of  pounds. 

The  apparatus  is  made  up  of  a  supporting  base,  a  self-oiling  commercial  jack  of  best  quality,  a  power 
wheel  18  inches  in  diameter  grooved  for  cord,  a  lever  arm  8  feet  long  capable  of  sustaining  the  2-ton 


load  and  anchorage  bar. 

Without  weights  and  dynamometers . $29.60 

29-167  WEIGHTS  for  use  with  the  above,  unadjusted,  in  50-pound  units . Each  3.76 

29-169  HANGERS  for  weights,  unadjusted,  approximately  50  pounds . Each  6.26 


16-334  SIXTY  POUND  DYNAMOMETER,  60  pounds  by  pound,  as  illustrated  above  in  outline  .  .  .  3.20 


No.  29-180 


29-180  BENT-ARM  LEVER  AND  SUPPORTING  TABLE.  This  apparatus  has  been  developed  for  the  pur¬ 
pose  of  determining  the  relation  between  the  forces  acting  on  a  lever.  In  its  design  special  attention 
has  been  given  to  the  eliminating  of  all  directive  forces  due  to  gravity  and  friction,  and  enabling 
the  use  of  forces  of  large  dimensions. 

Without  Balances . $29.60 

16-332  TWENTY  POUND  DYNAMOMETER,  20  pounds  by  pound,  as  illustrated  above  in  outline  .  .  2.16 

WEIGHTS  AND  WEIGHT  HANGERS.  See  Section  16. 


128 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MECHANICS  OF  LIQUIDS 

DENSITY  AND  SPECIFIC  GRAVITY 


No.  31-10 


Nos.  31-20  to  31-27 


No.  31-35 


31-10  ARCHIMEDES’  PRINCIPLE  for  demonstrating  that  a  body  submerged  in  water  displaces  an  amount 
equal  to  its  own  volume. 

This  apparatus  consists  of  a  solid  cylinder  and  bucket  accurately  machined  so  that  the  cylinder  will 
exactly  fit  and  fill  the  bucket.  Each  is  provided  with  hooks  and  the  bucket  is  further  provided 
with  a  handle. 

Polished  and  lacquered . $1.20 

31-18  OVERFLOW  CAN  AND  CATCH  BUCKET  for  formulating  Archimedes’  Principle.  This  apparatus 
consists  of  a  nickel-plated  spring  brass  Can  with  overflow  spout  near  the  top.  The  Catch  Bucket, 
also  of  nickel-plated  spring  brass,  is  provided  with  a  handle  and  is  of  convenient  height  for  placing 
under  overflow  spout.  In  use,  the  Catch  Bucket  is  placed  under  the  mouth  of  the  spout  and  the 
Overflow  Can  filled  until  water  begins  to  flow.  When  flow  has  ceased,  the  water  in  the  Catch 
Bucket  is  discarded  and  the  Bucket  is  replaced.  If,  now,  an  object  is  placed  in  the  Overflow  Can, 
there  is  an  outflow  from  the  Can  into  the  Catch  Bucket  which  exactly  equals  the  volume  of  the 


body. 

Overflow  Can  and  Catch  Bucket .  .90 

31-20  OVERFLOW  CAN . 65 

31-21  CATCH  BUCKET . 36 

31-23  LOADED  WATERPROOF  WOODEN  CYLINDER,  adapted  for  use  in  Displacement  and  Density 

experiments. 

This  is  a  cylinder  loaded  to  just  sink  in  water,  with  a  water-proof  paraffine  finish.  It  is  especially 

adapted,  from  its  size  (3J^  inches  by  1 %  inches  diameter),  for  use  with  Overflow  Can  No.  31-20  .  .16 

31-25  WATERPROOF  CHERRY  BLOCK,  useful  as  specimen  for  measurement  as  well  as  for  experimentation 
and  density  work. 

This  block  is  made  of  cherry  with  sandpaper  finish  and  paraffined  to  make  water-proof.  Its  size  is 

3  X  3  X  lJi  inches  thick,  which  makes  it  especially  adapted  for  individual  student  work  ....  .11 


31-27  LOADED  WATERPROOF  RECTANGULAR  BLOCK  for  Displacement  and  Density  experiments. 

This  is  a  block,  1%  inches  square  by  2%  inches  high,  loaded  to  just  sink  in  water  and  made  water¬ 
proof  by  boiling  in  paraffine  .  _ . f .  .18 

31-35  LEAD  SINKER  for  determining  the  Specific  Gravity  of  Lead,  and  for  use  as  Sinker  in  determining  the 
Specific  Gravity  of  an  object  lighter  than  water. 

This  Sinker  is  of  uniform  density  and  of  convenient  mass  and  size  for  use  in  Density  experiments.  It 

is  provided  with  small  brass  hook  for  suspension .  .13 

31—40  SULPHUR  SPECIMEN  for  the  determination  of  the  Specific  Gravity  of  Sulphur. 

This  is  a  specimen  about  3  inches  long  by  1)^  inches  in  diameter .  .06 

-31-45  SPECIFIC  GRAVITY  DETERMINATION  GROUP,  consisting  of  Nos.  31-20  to  31-40 .  1.64 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


129 


No.  31-60 


No.  31-67 


No.  31-85 


No.  31-80 


No.  31-105 


31-56  PURE  ALUMINUM  BLOCK,  of  commensurable  volume  for  use  in  determination  of  the  specific  gravity 
of  aluminum,  of  a  liquid  by  buoyancy  method,  of  a  solid  lighter  than  water  by  the  sinker  method. 

This  is  a  cubical  block  of  cast  metal,  1  y2  inches  on  an  edge  . $0.60 

31-60  ALUMINUM  CYLINDER,  after  Millikan,  Gale  and  Bishop’s  “Laboratory  Physics”  (Experi¬ 
ment  6) .  .54 

31-66  PARAFFINE  CUBE  for  density  experiments.  This  is  a  cast  cube  of  paraffine,  measuring  5  centi¬ 
meters  on  an  edge  and  weighing  approximately  100  grams .  .27 

31-67  SPECIFIC  GRAVITY  SPECIMENS  for  mensuration  and  specific  gravity  work. 

These  specimens  are  rods  of  y2  inch  diameter,  2  inches  long,  accurately  machined.  The  set  consists 

of  aluminum,  brass,  steel,  and  hard  rubber,  enclosed  in  small  cardboard  box .  .85 


31-67a  ALUMINUM  ROD,  H  X  2  inches . 24 

31-67b  BRASS  ROD,  y2  X  2  inches . •. . 18 

31-67c  STEEL  ROD,  X  2  inches . . ^  .16 

31-67d  HARD  RUBBER  ROD,  y2  X  2  inches . 29 

31-70  SPECIFIC  GRAVITY  SPECIMENS,  twenty  different  substances  of  irregular  shape,  of  convenient 

size  for  individual  student  work  in  density.  In  cardboard  box .  .66 

31-80  SPECIFIC  GRAVITY  SPECIMENS  for  exact  determinations  of  volume  by  direct  measurement; 

also  for  determination  of  density  by  measurement  of  mass,  illustrating  by  direct  comparison  the 
relations  between  volume,  mass  and  density. 

These  specimens  consist  of  twelve  cubes,  accurately  machined  to  exactly  one  centimeter  on  an  edge, 
thus  giving  a  volume  of  one  cubic  centimeter.  The  mass,  therefore,  of  each  cube  will  be  the  density 
The  set  consists  of  the  following  specimens,  —  one  each  of  magnesium,  aluminum,  zinc,  tin,  iron, 
nickel,  copper,  silver,  lead,  and  alloys  of  copper  and  zinc,  copper  and  aluminum,  and  copper  and 
tin.  Each  set  is  enclosed  with  index  in  a  velvet-lined  case .  9.85 


31-86  SPECIFIC  GRAVITY  SPECIMENS  for  showing  that  lengths  are  inversely  proportional  to  specific 
gravity  when  comparing  substances  of  same  diameter  and  mass;  also,  for  exact  determinations  of 
volume  by  direct  measurements. 

These  specimens  consist  of  twelve  cylinders,  machined  to  exactly  5  millimeters  in  diameter  and  length, 
adjusted  to  weigh  exactly  10  grams.  The  set  consists  of  same  metals  as  listed  under  No.  31-80, 
enclosed  in  velvet-lined  hinged  case,  with  index  on  under  side  of  cover . 10.85 

31-97  WATERPROOF  WOODEN  ROD  for  determination  of  the  specific  gravity  by  the  flotation  method. 

This  is  a  rod  of  wood  of  uniform  density,  20  centimeters  long,  1  centimeter  in  diameter,  coated  with 

paraffine  to  make  waterproof . .  .06 

31-100  BRASS  SUPPORT  for  holding  No.  31-97  in  vertical  position. 

This  is  a  spring  brass  support,  designed  to  clamp  securely  on  the  side  of  a  battery  jar  and  to  hold 

No.  31-97  in  an  erect  position  by  means  of  two  aligned  round  sockets . .  .17 

31-105  DENSITY  BY  FLOTATION  APPARATUS  consisting  of  Nos.  31-97  and  31-100  with  No.  31-266C 

Glass  Jar,  complete  •.  .  . . . . .  .63 


130 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  31-160 


31-126  SPECIFIC  GRAVITY  BOTTLE  WITH  THERMOMETER  STOPPER  for  determination  of  the 
specific  gravity  of  a  liquid  by  the  weight  of  a  measured  quantity;  capacity  50  cubic  centimeters  . 
31-130  SPECIFIC  GRAVITY  BOTTLE  WITH  CAPILLARY  STOPPER  for  determination  of  the  specific 
gravity  of  a  liquid  by  the  weight  of  the  measured  quantity.  Capacity  25  cubic  centimeters,  ac¬ 
curately  adjusted . . . 

31-131  -  — ,  same  as  above,  capacity  50  cubic  centimeters . 

31-132  - ,  same  as  No.  31-130,  but  unadjusted . 

31-136  SPECIFIC  GRAVITY  BOTTLE.  This  is  a  small,  glass-stoppered  bottle  of  convenient  size  frequently 

desired  by  instructors  in  preference  to  the  especially  adapted  types . 

31-140  SPECIFIC  GRAVITY  BOTTLE  WITH  CAPILLARY  STOPPER,  double-walled  and  evacuated. 

Capacity  25  cubic  centimeters . . . 

31-146  HARE’S  BALANCING  COLUMNS  APPARATUS.  This  apparatus  consists  of  a  support  at  the  top  of 
which  is  mounted  a  special  lead  tube  with  three  branches.  To  the  two  outside  branches  are  at¬ 
tached  two  lengths  of  glass  tubing;  to  the  central,  the  tubing  through  which  the  air  is  to  be  ex¬ 
hausted  from  both  tubes. 

Complete  as  illustrated,  with  clamp,  two  jars,  glass  and  rubber  tubing  connections  and  pinchcock, 
but  without  upright  support . 

31-146a  SPECIAL  LEAD  PIECE  WITH  THREE  BRANCHES  . 


31-146b  GLASS  TUBES  . Per  Pair 

31-146c  PINCHCOCK  . 

31-145d  GLASS  JARS . Per  Pair 


31-146e  UPRIGHT  SUPPORT  AND  CLAMP  . 

31-145f  SUPPORT  CLAMP  as  used  in  above  . 

31-160  SPECIFIC  GRAVITY  PLUMMETS  for  Lecture  Table  use. 

This  apparatus  consists  of  twenty-seven  plummets  indicating  by  sinking  or  floating,  Specific  Gravi¬ 
ties  ranging  from  .7000  to  2.000  by  steps  of  .0600. 

On  the  demonstration  desk,  if  placed  in  a  liquid  in  a  tall  jar,  and  other  liquids  which  do  not  mix  are 

carefully  placed  in  this  jar,  a  spectacular  result  follows . Duty  Free 

31-160  DENSITY  INDICATING  BALL  for  illustrating  the  changes  in  the  density  of  a  liquid  induced  by 
variations  in  temperature. 

This  is  a  metal  ball  75  millimeters  in  diameter,  nicely  adjusted  to  float  in  cold  water,  but  which  will 
sink  in  warm  water . 


$2.76 


.67 

.92 

.30 


.10 

2.16 


.96 

.27 

.20 

.20 

.20 

1.76 

48 


9.86 


3.86 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


131 


No.  31-170 


No.  31-227 


No.  31-226 


No.  31-266 


31-170  HYDROMETER  (CONSTANT  WEIGHT),  for  finding  Specific  Gravity  of  light  liquids, 


Beaume’s  Scale  70-10,  Specific  Gravity  Scale  0.7000  to  1.000  . . $0.60 

31-171  HYDROMETER  (CONSTANT  WEIGHT),  for  heavy  liquids,  Beaume’s  Scale,  0-70, 

Specific  Gravity  Scale  1.000  to  2.000  .  .60 


31-176  HYDROMETER  (CONSTANT  WEIGHT),  for  both  light  and  heavy  liquids . 

31-226  CONSTANT  VOLUME  HYDROMETER  TUBE,  after  Millikan,  Gale  and  Bishop’s  “Laboratory 

Physics” . 

31-227  CONSTANT  WEIGHT  HYDROMETER  TUBE,  after  Millikan,  Gale  and  Bishop’s  “Laboratory 
Physics,”  for  determining  the  Density  of  a  Liquid  by  the  flotation  method . 

31-230  DEMONSTRATION  HYDROMETER,  illustrating  the  principle  of  the  hydrometer  and  the  method 
of  determining  the  specific  gravity  of  liquids  by  buoyancy. 

This  is  a  paraffined  rod,  30  centimeters  in  length,  1  square  centimeter  cross  section,  graduated  the 
entire  length  to  millimeters.  Without  Jar  .  .• . 


31-232 

31-240 


31-242 

31-250 


31-266 


with  Jar 


NICHOLSON’S  HYDROMETER  for  determining  the  Density  of  a  Body  Heavier  than  Water. 
This  is  a  Constant  Volume  Hydrometer  constructed  of  metal.  It  consists  of  a  hollow  cylinder  at¬ 
tached  to  the  lower  end  of  which  is  a  basket  heavy  enough  to  keep  the  cylinder  upright;  at  the 

upper  end  is  a  vertical  rod  carrying  a  pan  for  holding  weights.  Without  Jar . 

_ ;  same  as  above,  but  made  entirely  of  glass.  Recommended  for  lecture  use.  Without  Jar  .  . 

CLEAR  WHITE  GLASS  HYDROMETER  JARS  for  use  where  a  tall  jar  of  small  diameter  is  desired. 


Size,  inches  .  12  X 

Price  .  .  .  $0.60 

GLASS  JARS,  of  excellent  quality. 

a 

Size,  inches  .  2\i  X 

Price  .  .  .  $0.12 


12  X  2 

15  X  2 

15  X  3 

$0.65 

$0.80 

$1.00 

b 

c 

d 

4X5 

6X8 

8  X  12 

$0.26 

$0.40 

$1.60 

18  X  3 

$1.36 


1.26 


.33 


.44 


.20 


.76 


1.95 

2.95 


132 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  20 -tol 


No.  20-260 


No.  32-30 


No.  32-36 


20-261  INCOMPRESSIBILITY  OF  LIQUIDS  APPARATUS,  IMPROVED  DESIGN,  for  the  quantitative 

observation  of  the  incompressibility  of  liquids. 

This  apparatus  consists  of  a  tube  with  indicating  capillary.  The  liquid  to  be  observed  should  fill 
the  short  arm  of  the  tube  and  should  rise  in  the  long  arm  to  near  the  top  of  the  capillary.  If  mer¬ 
cury  is  poured  into  the  long  arm,  the  liquid,  if  compressible,  will  indicate  the  amount,  if  any,  in  the 
capillary. 

This  tube  may  be  mounted  on  our  No.  41-116  Boyle’s  Law  Stand.  Tube  only . $2.60 

20-260  SCREW  ADJUSTMENT  INCOMPRESSIBILITY  OF  LIQUIDS  APPARATUS  for  showing  elas¬ 
ticity  and  incompressibility  of  liquids. 

This  apparatus  consists  of  a  support  which  answers  the  double  purpose  of  supporting  a  plunger  and 
a  bottle  as  well  as  that  of  a  clamp. 

In  use,  the  bottle  is  filled  with  the  liquid,  a  one-hole  rubber  stopper  placed  in  the  neck,  the  end  of 
the  plunger  placed  in  the  hole  and  the  bottle  clamped  firmly  in  place  by  means  of  a  screw  ad¬ 
justment.  If  the  plunger  is  now  thrust  into  the  bottle,  the  liquid  being  incompressible,  the  bottle 
will  burst. 

Complete  with  three  bottles .  1.46 

32-30  UNIFORM  PRESSURE  SYRINGE  OF  BRASS  for  demonstrating  that  the  pressure  of  liquids  is 
equal  in  all  directions  against  the  sides  of  the  containing  vessel. 

This  apparatus  consists  of  a  metal  sphere  to  which  is  attached  a  brass  tube  with  piston.  On  the 
surface  of  this  sphere  are  “bosses”  into  which  glass  tubes  are  sealed  in  a  vertical  position.  If  the 
apparatus  is  filled  with  water,  or  any  other  liquid  inactive  on  the  metal,  any  pressure  exerted  by 
the  piston  will  be  transmitted  in  all  directions  against  the  inner  sides  of  the  sphere.  As  this 
pressure  is  equal  in  all  directions,  the  water  will  rise  from  the  glass  tubes  a  uniform  distance. 

This  is  a  convenient  form  for  the  demonstration  of  the  principle  involved,  and  the  accuracy  of  the 

result  and  the  cleanliness  of  operation  make  it  a  valuable  addition  to  a  laboratory  equipment  .  .  12.00 

32-36  UNIFORM  PRESSURE  SYRINGE  for  demonstrating  that  the  pressure  of  liquids  is  equal  in  all 
directions  against  the  sides  of  the  containing  vessel. 

This  is  an  apparatus  similar  in  design  to  the  above,  but  made  of  glass,  without  the  pressure  indicating 

tubes.  The  equality  of  pressure  is  illustrated  by  the  spouting  liquid .  1.96 


PRESSURE  OF  LIQUIDS 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


133 


32-50  PRESSURE 
GAUGE,  with 
Equalizing  Tube 

after  Cheston, 

Dean  and  Tim- 
merman’s 
“Labor a  t  o  rv 
Manual  of 

Physics”  (Experiment  4),  for  measuring  directly 
the  pressure  of  liquids  at  various  depths. 

This  apparatus  consists  of  a  Pressure  Diaphragm  in 
direct  connection  with  a  Manometer,  the  whole 
mounted  on  a  wooden  scale.  This  form  is  an  im¬ 
provement  over  the  old  types,  in  that  the  level  of 
No.  32-50  the  liquid  in  the  Manometer  may  instantly  be  made 

the  same  in  both  branches  by  allowing  an  equality 
of  pressure  by  opening  the  horizontal  tube  noted  in 
the  illustration  at  about  the  central  point  ....  $1.36 


32-60  CHAIN  DRIVE  PRESSURE  GAUGE,  HALL’S  IMPROVED,  for 

demonstrating  that  pressure  upon  a  surface  varies  with  the  depth 
but  not  with  the  angle  of  inclination. 

This  apparatus  has  been  greatly  improved  to  obviate  the  deteriorat¬ 
ing  quality  of  the  rubber  belt  as  used  in  former  designs,  the  uni¬ 
versal  movement  of  the  pressure  chamber  being  imparted  by  a 
chain  and  sprocket  operated  by  a  small  crank.  Illustration  pic¬ 
tures  also  our  No.  32-62  Pressure  Gauge  Attachment,  valuable 
when  it  is  desired  to  project  the  indicating  globule  on  a  screen. 
Pressure  Gauge  only,  without  Jar  or  Attachment .  2.80 


Nos.  32-60  and  32-62 


32-62  PRESSURE  GAUGE  PROJECTION  HOLDER,  as  designed  by  Dr.  Hall,  for  use  in  the  lantern  slide 
carrier  in  projecting  the  indicating  globule  in  Manometer  Tube  of  above. 

This  Holder  is  designed  to  fit  the  Standard  Lantern  Slide  Carrier.  The  Manometer  Tube,  as  il¬ 
lustrated  above,  is  clamped  by  two  discs  eccentrically  mounted.  The  globule  shows  through  the 
center  of  the  opening.  Holder,  only . $0.66 


32-66  PRESSURE  GAUGE,  simple  form,  consisting  of  a  pressure  chamber  in  con¬ 
nection  with  an  index  tube  .  .18 

32-66  LIQUID  PRESSURE  GAUGE,  after  Millikan  and  Gale,  Figure  4  .  .65 

32-70  GLASS  MANOMETER  TUBE,  after  Millikan,  Gale  and  Bishop  (Experi¬ 
ment  4) . . .  -27 


32-75  PRESSURE  TUBES,  after  Gage’s  “Introduction  to  Physical  Science,”  for 
showing  that  at  same  depth  pressure  is  equal  in  all  directions. 

The  set  consists  of  four  tubes,  U  form,  the  shorter  arms  of  which  open  in 
different  directions,  —  upward,  downward  and  sideways. 

In  use,  an  equal  amount  of  mercury  is  placed  in  the  bends  and  the  tubes  thrust 
into  a  jar  filled  with  the  liquid  until  the  openings  of  the  short  arms  are  all 
brought  at  the  same  depth.  The  pressure  indicated  by  the  mercury  regis¬ 
ters  the  same. 


Per  set  of  four  tubes 


.96 


134  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  32-100  (Fig.  1)  No.  32-100  (Fig.  2) 


32-100  NICHOLS’  UPWARD  AND  DOWNWARD  PASCAL’S  VASE  APPARATUS  for  quantitative 

determintaion  of  the  laws  governing  liquid  pressure,  both  upward  and  downward,  also,  that  pres¬ 
sure  upon  a  surface  is  independent  of  the  shape  of  the  containing  vessel. 


The  apparatus  consists  of  a  standard  to  which  are  attached  the  various  supporting  arms  of  which 
three  are  used  in  the  experiment.  (See  Fig.  1  above.) 

DOWNWARD  PRESSURE.  This  apparatus  shows  the  method  of  assembling  when  it  is  desired  to 
measure  the  downward  pressure,  its  relation  to  the  size  of  the  surface  acted  upon,  the  effect  of  the 
amount  of  liquid  in  the  vessel  above  the  surface  and  the  perpendicular  height  of  the  liquid. 


If  water  is  then  poured  into  the  vessel,  the  upward  pressure  will  be  indicated  by  the  long  arm  of  the 
lever  moving  upward.  The  amount  of  pressure  may  be  calculated  from  the  factors  obtained  by 
the  measurements  of  the  two  arms  of  the  lever. 

UPWARD  PRESSURE.  Fig.  2  illustrates  how  the  apparatus  is  assembled  for  the  study  of  upward 
pressure  of  a  liquid  on  a  submerged  surface,  showing  that  the  upward  pressure  bears  the  same 
relation  to  the  depth  as  does  the  downward  pressure. 


The  apparatus  is  substantial  and  beautifully  constructed  throughout.  Attractive  dark  finish  with 
nickel-plated  fittings-  The  design  is  such  as  to  permit  of  exact  determinations  with  the  least 
inconvenience  in  manipulation.  We  call  especial  attention  to  its  compactness,  stability,  and  its 
cleanliness  in  operation. 


Complete  with  all  parts 


$18.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


135 


No.  32-110 


1 


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Cn  0>  O  d  U> 


—  M 

llllUlulllllUil 


Ol  Oi  s|  cb  (g 


k  (A  a,  S  a 

Ulllllllllll.lllllll.lllllll.lll 


ts*  u  (n 


iil..il.iil.i.lmliiiliiiil.iili.iliii'iiliiilii. 


—KN  Of  Tj  BOSTON  — 


—  nu/A'Oicnvjme  a  —  Nu^o*d*Jn>ioc-^rooi^Cn«n'J»*«>o-w<*-^0»d'*®u>o—  N<u>uid>jo>Wj 

ulim(niJRniiMlMu!iHiliii!.nilin  lm4ifhiiInJmiln>lNii(miki.hnbiu«.iriiiuUiiiluthuibinbiilnnhi.i^lii.ihiiilMnlmiWoliiiiliuiluul.mliutU.iliuilmiluiliiul'.i.uh.l<iir.hmiuiiWli<!iluutKilmi.iiiM 


No.  32-130 

32-110  PASCAL’S  VASES  WITH  BALANCE  ARM  AND  WEIGHT  for  demonstrating  that  pressure  is  in¬ 
dependent  of  the  shape  of  the  containing  vessel. 

The  apparatus  consists  of  a  casting  for  supporting  the  vessels  of  different  shapes,  also  for  a  standard 
which  carries  at  its  top  a  pivoted  lever,  on  the  short  arm  of  which  may  be  attached  a  hanger  bear¬ 
ing  a  brass  disc  the  surface  of  which  is  ground  to  fit  a  cylindrical  part  of  the  casting  above  men¬ 
tioned. 

In  use,  the  hanger  is  balanced  by  placing  weights  on  the  long  arm  of  the  lever.  An  index  attached 
to  the  standard  indicates  the  height  of  the  water  in  the  vessel. 

The  hanger  is  attached  to  the  arm  of  a  balance. 

Complete,  as  illustrated  with  jar  and  three  vessels  of  different  shapes,  balance  arm  and  weights  .  .  $6.35 

32-115  PASCAL’S  VASES  WITH  MERCURY  INDICATOR  for  demonstrating  that  pressure  is  independent 
of  the  shape  of  the  containing  vessel,  depending  only  on  the  area  pressed  upon. 

The  illustration  pictures  an  instrument  made  entirely  of  glass.  It  consists  of  three  differently 
shaped  vessels,  each  connected  through  stop-cocks  of  equal  bore  to  a  common  tube  terminating  at 
each  end  in  manometer  tubes,  which,  in  use,  have  their  bends  filled  with  mercury,  which  acts  as 
the  pressure  indicator. 

This  instrument  has  become  popular  from  its  quality  of  being  self-contained.  Besides  its  extreme 
sensibility,  its  convenience  in  operating  and  its  cleanliness,  this  instrument  is  commended  for  the 

rapidity  with  which  it  can  be  operated .  6.76 

32-120  BUOYANCY  OF  LIQUIDS  APPARATUS  for  illustrating  vertical  upward  pressure. 

This  apparatus  consists  of  a  glass  disc  the  surface  of  which  is  ground  to  fit  the  lower  rim  of  a  glass 
cylinder.  In  use,  this  disc  is  held  in  junction  to  the  cylinder  by  means  of  a  string  attached  to 
the  center  of  the  disc  until  a  buoyancy  pressure  sufficient  to  counteract  the  weight  of  the  disc  is 
reached.  This  pressure  may  be  measured  by  carefully  pouring  water  into  the  cylinder  until  the 
mass  equalizes  the  buoyancy  pressure  of  the  liquid  on  the  disc. 

Complete  as  illustrated,  with  jar,  glass  cylinder,  disc,  and  support  for  cylinder .  1.64 

32-130  LIQUID  PRESSURE  TUBES,  after  Chute’s  “Physical  Laboratory  Manual,”  Problem  62,  for  verify¬ 
ing  the  Laws  of  Liquid  Pressure. 

These  tubes  are  of  glass,  50  centimeters  long,  of  different  diameters,  graduated  into  millimeters  along 

their  entire  length,  the  zero  of  the  scales  being  at  the  closed  ends . Per  Pair  2.76 

32-132  CYLINDRICAL  GLASS  VESSEL  for  use  with  above  Liquid  Pressure  Tubes .  2.50 

32-134  LOADED  GRADUATED  LIQUID  PRESSURE  TUBE,  after  Fuller  and  Brownlee . 36 

32-136  PRESSURE  U-TUBES  for  experiments  in  Fluid  Pressure,  consisting  of  tubes  with  arms  of  equal 
lengths. 

a  b  c  d  e 

Length  ...  10  12.5  15  30  50  centimeters 

Price  .  .  .  $0.14  .16  .18  .30  .60 


136 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  32-150 


No.  32-160 


- 


No.  32-165 


32-160  TORRICELLIAN  LAW  APPARATUS  for  determination  of  the  law  s  equals  \/  2  gh,  where  5  equals 
the  speed  of  efflux,  g  the  value  of  gravity  and  h  the  height  of  the  liquid;  also  for  simple  demon¬ 
stration  of  variable  pressure  according  to  depth  below  the  free  surface  of  the  liquid. 

This  apparatus  consists  of  a  tall  glass  cylinder  with  lateral  openings,  three  closed  by  stop-cock  tubes, 
the  fourth  terminating  in  a  tube  with  a  vertical  branch  which  may  be  stopped  by  rubber  tubing 
and  pinchcock.  If  the  liquid  is  allowed  to  issue  vertically  it  will  rise  to  nearly  the  height  of  the 
free  surface  of  the  liquid  in  the  jar.  This  height  would  be  the  same  except  for  the  friction  at  the 
orifice,  the  weight  of  the  falling  liquid  and  the  resistance  of  the  air.  By  turning  the  stop-cocks  in 
the  other  lateral  tubes,  allowing  the  liquid  to  issue  forth,  it  will  be  noted  that  the  pressure  varies  as 
the  depth  of  the  orifice  below  the  free  surface,  the  paths  of  the  issuing  stream  following  a  parabolic 
curve  due  to  the  force  of  gravity.  By  observation  and  calculation  it  may  be  determined  that  the 
focus  of  these  parabolic  curves  is  as  much  below  the  orifice  as  the  surface  of  the  liquid  is  above  it 
and  that  the  curves  are  flatter  the  greater  the  pressure  under  which  they  issue. 


Complete  as  illustrated . .  $7.90 

32-160  MARIOTTE’S  BOTTLE,  after  Hall  &  Bergen’s  “A  Text-Book  of  Physics,”  page  44,  for  the  study 
of  Fluid  Pressure  at  varying  levels. 

Complete  as  illustrated,  with  rubber  stoppers  and  glass  fittings . .  3.75 


32-165  EIGHT-IN-ONE  APPARATUS,  after  Gage’s  “Introduction  to  Physical  Science”  (Experiment 
32)  for  the  study  of  the  Torricellian  Laws,  as  described  under  No.  32-160. 

This  apparatus,  advised  for  Lecture  Table  work,  consists  of  a  brass  cylinder,  6  feet  long,  surmounted 
by  a  reservoir.  At  various  heights  along  the  tube  are  attached  lateral  tubes  with  screw  caps.  By 
the  successive  openings  of  these  screw  caps,  the  paths  of  the  issuing  streams  are  readily  observed. 

It  will  be  noted  that  the  stream  issuing  from  the  lowest  orifice  shows  flattest,  thus  showing  the  great¬ 
est  pressure.  The  streams  issuing  from  the  other  orifices  all  take  a  curved  path,  the  curvatures, 
however,  depending  upon  the  depths  of  the  orifices  below  the  free  surface  of  the  liquid  ....  8.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


137 


No.  32-180 


!2  180  LIQUID  LEVEL  APPARATUS,  IMPROVED  FORM,  for  illustrating  the  tendency  of  a  liquid  to  seek 
its  own  level. 

This  apparatus  consists  of  a  cast-iron  reservoir  with  open  tubulatures  into  the  top  of  which  are  set 
glass  tubes  of  various  shapes  and  sizes.  A  liquid  poured  into  the  funnel-shaped  tube  will  fill  the 
iron  reservoir  and  rise  in  the  tubes  at  equal  rates  and  remain  at  the  same  height.  The  U-shaped 
tube  has  branches  of  equal  area. 

This  apparatus  must  not  be  confused  with  other  designs.  Our  design  is  of  substantial  construction, 

handsome  in  appearance,  obviating  the  inconveniences  of  less  modern  types . $3.30 

12-186  LIQUID  LEVEL  COMMUNICATING  TUBES  for  illustrating  the  tendency  of  a  liquid  to  seek  its 
own  level. 

This  apparatus,  constructed  entirely  of  glass,  consists  of  four  tubes  of  different  shapes  and  sizes 

communicating  with  each  other  by  means  of  a  common  connection .  .75 


No.  32-205 


No.  32-216 


No.  32-230 


12-200  SIMPLE  SIPHON  for  the  qualitative  and  quantitative  study  of  the  principles  involved. 

Consists  of  a  glass  tube,  bent  in  shape  as  illustrated.  Length  of  arm,  12  inches . $0.20 

12-206  SIPHON  WITH  SUCTION  TUBE . 36 


12-215  TANTALUS  CUP  OR  INTERMITTENT  FOUNTAIN,  illustrating  the  principle  of  Intermittent 
Springs. 

This  standard  design  is  in  reality  a  Siphon,  the  long  arm  of  which  is  held  in  a  stopper  in  the  constric¬ 
tion  of  the  goblet-shaped  glass  vessel. 

In  use,  water  is  led  into  the  goblet.  This  water  will  rise  in  the  short  arm  of  the  siphon  until  it  reaches 
the  bend,  when  it  will  flow  down  through  the  long  arm  of  the  siphon  and  continue  to  flow  until 
the  level  of  the  water  gets  below  the  end  of  the  short  arm.  This  action  will  be  continuous  if  the 
inflow  through  the  siphon  is  less  than  the  outflow .  .70 

>2-230  CARTESIAN  DIVER,  illustrating  the  different  effects  of  suspension,  immersion,  and  floating. 

The  apparatus  as  illustrated  is  instructive  and  amusing,  as  the  little  figure  is  susceptible  to  the 
least  movement  of  the  diaphragm,  causing  it  to  go  through  some  very  peculiar  antics. 

Complete  as  illustrated .  .80 

2-231  CARTESIAN  DIVER,  only . 26 


138 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


34-10 


34-20 


34-30 


34-40 


T 


•  > 


No.  34H0 


No.  34-30 


No.  34-40 


HYDRAULIC  POWER  PRESS  for  illustrating  the  force  of  a  Hydraulic  Press. 

The  instrument  illustrated  is  more  than  a  model,  in  that  it  may  be  subjected  to  very  severe  tests  for 
breaking  strengths.  It  is  built  of  cast  iron,  bronze  and  steel  throughout,  all  parts  being  finished 
as  strikingly  as  possible.  The  cylinders  are  accurately  turned  and  fit  perfectly,  the  large  one 
having  an  internal  diameter  of  inches,  the  small  cylinder  of  the  force  pump  being  %  of  an  inch. 
In  working  our  design,  or  in  working  any  design  of  Hydraulic  Press  we  advise  the  use  of  oil,  inas¬ 
much  as  this  liquid  prevents  wear  of  the  working  parts. 

This  instrument  has  been  subjected  to  very  severe  strains  in  our  laboratory  and  each  instrument 
shipped  is  tested  to  give  the  calculated  efficiency . 

HYDRAULIC  PRESS  for  the  study  of  the  principle  involved  in  the  Hydraulic  Press. 

This  is  the  standard  simple  model  of  glass,  the  valves  of  which  are  colored  so  that  their  operation 
may  readily  be  observed . . . 

SIX-FOOT  WATER  HEAD  HYDROSTATIC  BELLOWS  for  illustrating  an  application  of  Pascal’s 
Law. 

Our  design  consists  of  a  strongly  constructed  bellows  30  centimeters  square,  supported  by  legs. 
Attached  to  this  bellows  is  a  brass  tube  upright,  6  feet  long,  terminating  at  its  top  in  a  conical  reser¬ 
voir.  This  upright  is  separable  into  two  parts  as  illustrated.  All  parts  are  handsomely  finished 
and  designed  to  withstand  reasonable  strain,  the  pneumatic  bellows  being  sufficiently  strong  to 
hold  a  person . 

SEVEN-IN-ONE  APPARATUS  OR  SPIROMETER,  GAGE’S  IMPROVED,  for  demonstrating 
fundamental  principles  in  Pneumatics  and  Hydraulics. 

This  apparatus  consists  of  a  seamless  brass  cylinder,  6  inches  in'diameter,  mounted  on  a  metal  casting, 
provided  with  “bosses,”  into  which  rods  may  be  screwed  from  either  side.  The  cylinder  is  provided 
with  an  ingeniously  designed  piston  which,  owing  to  its  construction,  has  greater  efficiency,  the 
longer  the  use.  This  construction  also  obviates  the  sticking  of  the  washers  and  leakage  around 
them.  Each  instrument  is  provided  with  our  detachable  handle  in  the  piston  head,  a  fixed  handle 
with  brass  stopcock,  and  nipple.  This  apparatus,  as  implied  from  the  name  “Seven-in-One,”  will 
illustrate  the  principle*  involved  in  seven  different  instruments,  as  follows:  —  Hydraulic  Lift, 
Hydraulic  Press,  Incompressibility  of  Liquids  Apparatus,  Pascal’s  Law  Apparatus,  Pneumatic 
Lift,  Hydrostatic  Bellows,  and  Magdeburg  Hemispheres. 

It  is  handsomely  finished  in  nickel  plate  and  is  furnished  complete  with  rods  for  supports  .  .  .  . 


$34.60 


1.66 


22.60 


8.90 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


139 


RAMS  —  PUMPS 


No.  35-10 


No.  35-15  (Sectional  View) 


No.  35-20 


No  35-16 


35-10  HYDRAULIC  RAM,  illustrating  the  increase  of  pressure  due  to  interrupted  flow  in  a  stream  of  water. 
This  model  is  made  entirely  of  glass,  with  black  glass  valve.  It  is  mounted  on  a  wooden  base;  its 
size,  17  X  13  inches,  is  ample  for  lecture  hall  demonstration . 


36-16  HYDRAULIC  RAM,  commercial  form.  By  referring  to  the  sectional  view  it  will  be  noticed  that  it 
consists  of  an  Air  Chamber  A,  the  Body  B,  and  the  Snifting-Valve  for  Air  Inlet  C.  The  Check 
or  Inlet  Valve  E  is  located  between  the  supply  pipe  and  the  air  chamber.  The  Impetus  Valve  F 
is  located  at  the  end  of  the  supply  pipe. 

The  water  flowing  through  Supply  Pipe  G  passes  through  the  outlet  in  the  impetus  valve  until  the 
increasing  velocity  creates  sufficient  pressure  to  close  the  valve  checking  the  flow  of  water  in  this 
direction,  and  to  force  open  the  Check  Valve  E.  The  water  having  passed  into  the  air  chamber, 
is  then  forced  through  the  Delivery  Pipe  H  by  the  increased  pressure  on  the  air  chamber.  After 
forcing  the  water  into  the  air  chamber,  the  pressure  is  relieved  and  the  impetus  valve  opens,  only 
to  go  through  the  operation  again  and  again,  continually  delivering  water.  A  supply  of  from  2 
to  3  gallons  per  minute  is  required  to  operate  this  valve  successfully.  Size  of  drive  pipe,  %  inch; 
discharge  pipe,  )4  inch  diameter;  total  approximate  weight  27  pounds.  Capacity  60  to  100  gal¬ 
lons  per  hour  to  a  height  of  60  feet . 

36-20  COMMERCIAL  DEMONSTRATION  HYDRAULIC  RAM,  similar  in  construction  to  No.  35-16, 
yet  it  has  vastly  greater  pedagogic  value  in  that  the  air  chamber  is  of  glass,  permitting  view  of  the 
working  parts  in  actual  operation  without  in  the  least  taking  away  from  its  practical  commercial 
value  . 


$3.95 


11.00 


18.00 


140 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  36-30 


No.  36-66 


36-30  MODEL  OF  LIFT  PUMP,  entirely  of  glass  with  colored  glass  valve,  with  ground  seat.  Total  length 

15  inches .  . $1.60 


36-32  MODEL  OF  FORCE  PUMP,  made  entirely  of  glass,  with  black  glass  valves,  with  ground  seats  .  .  1.96 

36-40  FIRE  ENGINE  PUMP,  illustrating  the  practical  application  of  the  simple  force  pump. 

This  pump  is  in  reality  a  double  force  pump  with  a  central  reservoir  having  a  discharge  tube.  Its 
practical  application  will  be  found  in  the  walking  beam  fire  engine  pump. 

This  model  is  entirely  of  glass,  the  valves  being  constructed  of  black  glass  with  ground  glass  seats  .  .  2.26 


36-60  T-BEAM  WATER  LIFT  PUMP  for  use  with  our  No.  6-1000  Universal  T-Beam  Basic  Clamp  “A.” 

In  this  design,  we  present  a  pump  that  is  patterned  after  commercial  forms,  constructed  so  that  all 
working  parts  are  in  full  view.  Cylinder  inches  diameter,  capable  of  lifting  a  large  amount  of 
water. 

Without  Clamp .  7.86 

36-62  T-BEAM  WATER  FORCE  PUMP  for  use  with  our  No.  6-1000  Universal  T-Beam  Basic  Clamp  “A.” 

This  pump  has  the  same  commendable  features  as  the  above. 

Without  Clamp .  7.86 

Note.  These  Pumps  may  be  used  the  same  as  the  old  form  of  metal-fitted  glass  cylinder  pumps  in  case  the 
T-Beam  Clamp  is  not  provided.  When  so  used,  the  attachment  serves  as  a  broad,  flat  base  for  supporting.  The 
T-Beam  Clamps  for  holding  the  pumps  rigidly  to  the  table  will,  however,  prevent  accidental  breakage  and  will  be 
found  a  wise  investment. 

• 

36-66  T-BEAM  LIFT  AND  FORCE  PUMPS  WITH  TANK.  This  outfit  includes  the  Lift  and  Force  Pumps 
Nos.  36-60  and  36-62  above  and  the  T-Beam  Basic  Tank  No.  36-67  below. 

Complete  outfit  .  .  .  .* . - . $21.46 


36-67  T-BEAM  BASIC  TANK.  This  tank  is  the  same  as  furnished  in  above.  It  is  a  special  casting  with 
side  brackets  each  with  double-beveled  lathe-rest  slides  for  the  interlocking  bases  of  the  pumps.  It 
has  a  durable  black  finish  and  presents  a  pleasing  appearance  in  the  laboratory. 

Its  use  as  a  general  water  tank  for  many  experiments  should  not  be  overlooked .  6.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


141 


No.  35-76 


36-76  MODELS  OF  VALVES.  In  the  models  above  illustrated,  we  demonstrate  the  most  important  valve 
types,  as  follows,  —  butterfly  valve,  bellows  valve,  round  spring  valve,  conical  valve  and  oil  silk 
valve.  These  models  are  ample  in  size  for  lecture  work  and  follow  closely  the  commercial  types. 

Each  6  inches  in  diameter,  carefully  made  and  neatly  finished. 

Per  set  of  five  as  above  ....  . $5.50 


36-12  HERO’S  FOUNTAIN,  illustrating  the  raising  of  water  by  the  elastic  force  of  air.  Made  entirely  of 
glass,  in  form  as  illustrated. 

In  operation,  the  upper  bulb  is  first  filled  with  water,  the  lower  with  air.  The  fountain  is  started  by 
pouring  a  small  quantity  of  water  into  the  reservoir.  As  this  flows  down,  it  exerts  a  pressure  on 
the  air  contained  in  the  lower  bulb.  This  pressure  is  transferred  to  the  water  in  the  upper  bulb 
and  forces  it  out  through  the  fountain  nozzle . $2.70 

36-30  REACTION  APPARATUS,  illustrating  the  reactive  force  of  a  laterally  escaping  stream  of  liquid. 

The  apparatus  consists  of  a  glass  reservoir  with  fused-on  glass  indicator  at  the  bottom  and  a  small 
opening  through  which  the  liquid  may  flow  at  the  side.  If  the  reservoir  is  suspended  and  filled  with 
water,  the  reactive  force  of  the  issuing  liquid  through  the  opening  above  mentioned  will  cause  a 
movement  opposite  to  that  in  which  the  water  is  flowing. 

Complete  as  illustrated,  with  stationary  indicating  point .  1.00 

36-35  ACTION  AND  REACTION  APPARATUS,  after  Hall,  No.  XLV .  1.40 

36-50  REACTION  GAS  AND  FLAME  WHEEL  for  determining  the  reaction  set  up  by  gas  escaping  from 
a  lateral  opening. 

The  slightest  flow  of  a  gaseous  body,  from  whatever  cause,  passing  through  the  four  horizontal  arms 
will  cause  a  reaction  on  the  same  principle  as  in  Barker’s  Mill.  If  the  illuminating  gas  issuing 
from  these  four  orifices  be  ignited,  the  effect  is  spectacular  in  the  extreme. 

Price  complete,  as  above  illustrated .  2.60 

36-75  APPARATUS  FOR  STUDYING  WATER  FRICTION  IN  PIPES,  designed  by  Professor  E.  H.  Hall  of 
Harvard  University,  for  studying  the  effect  of  the  friction  in  pipes,  tending  to  impede  the  flow 
of  liquids. 

As  indicated  in  the  diagram,  both  branches  of  the  liquid  tube  have  the  same  liquid  pressure  impressed 
upon  them,  pipes  being  of  the  same  size,  differing  only  in  length,  while  the  amount  of  water  which 
passes  through  the  long  pipe  is  approximately  one-half  that  which  passes  through  the  short  pipe. 
Without  glasses .  2.26 

36-100  ACTION  AND  REACTION  STRIP,  after  Hall  (Experiment  XL VI) . 95 


142 


L  .  E  .  KNOTT  APPARATUS  CO.,  BOSTON 


WATER  TURBINES— WATER  WHEELS 


No.  37-30 


No.  37-20 

37-16  DEMONSTRATION  MODEL  OF  A  TURBINE.  This  is  an 
illustrative  model  for  the  teaching  of  the  fundamental  parts 
of  a  Water  Turbine.  It  is  substantially  constructed  of  glass 
and  metal,  all  working  parts  being  in  full  view.  The  central 
No.  37-16  shaft  transmits  motion  through  miter  gears  to  a  horizontal  shaft 

which  carries  a  pulley  wheel  which  may  be  connected  to  show 
power. 

This  model  is  handsomely  finished  and  substantially  constructed.  It  is  42  centimeters  high.  —  ample 

for  clear  view  from  all  parts  of  the  ordinary  lecture  room . Duty  Free  $52.75 


37-20  MODEL  OF  A  WATER  TURBINE  for  connection  to  a  water  pump. 

This  is  of  simple  construction  of  glass  and  brass  illustrative  of  same  principles  involved  in  more  ex¬ 
pensive  models . 


4.50 


37-30  MODEL  OF  WATER  TURBINE.  This  model  from  its  design  is  especially  adapted  to  lecture  work. 

It  is  sufficiently  large  for  class  demonstration  and  yet  will  develop  power  for  demonstrating  the 
commercial  value  of  a  turbine.  On  the  demonstration  side  it  has  the  feature  of  a  glass  front  which 
allows  full  inspection  of  all  working  parts.  The  model  is  carefully  constructed  and  handsomely 
finished,  the  parts  within  painted  a  distinguishable  color.  It  is  mounted  on  a  firm  supporting  base  13.60 


37-50  CAST  METAL  WATER  WHEEL  MODEL  for  study  and  demonstration  of  the  overshot,  undershot, 
and  breast  water  wheels.  In  our  design,  which  must  not  be  confused  with  types  on  the  market, 
we  furnish  not  only  an  accurately  constructed  instrument  but  one  that  is  durable  and  handsome 
in  appearance.  Our  runway  is  cast  of  metal  and  neatly  finished.  The  reservoir,  also  of  cast  metal, 

is  peculiar  in  design  in  that,  by  the  use  of  one 
water  wheel,  we  can  by  changing  its  position 
demonstrate  either  the  overshot  or  undershot 
wheels.  As  illustrated,  the  model  is  set  up  for 
an  overshot  wheel.  If  desired  to  demonstrate 
an  undershot  wheel  the  water  reservoir  must  be 
moved  back  to  position  indicated  by  dotted  line 
and  the  water  wheel  reversed. 

As  may  be  noted  from  our  illustration  this  model 
is  distinctive  in  design,  scientifically  constructed, 
and  we  have  no  hesitancy  in  claiming  for  it  a 
place  in  a  catalogue  of  scientific  instruments. 
Its  substantial  structure,  symmetry  of  lines,  and 
handsome  appearance  will  recommend  it  to  all  . 


6.90 


No.  37-60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


143 


37-60  EXTENSION  HEAD  BARKER’S  MILL  for  demonstrating  the 
horizontal  pressure  of  a  liquid  on  the  containing  vessel. 

The  design  above  illustrated  has  features  which  obviate  all  an¬ 
noyances  of  the  existing  types,  facilitate  the  proper  cleanly 
conduct  of  the  experiment,  and  present  a  handsome  and  scien¬ 
tific  appearance. 

This  apparatus  stands  about  3Yi  feet  high,  is  handsomely  fin¬ 
ished  throughout  and  ranks  well  with  other  scientific  instru¬ 
ments  . $4.50 


No.  37-60 


WATER  MOTORS 


No.  38-20 


No.  38-26 


38-20  THE  IMPROVED  WALTHAM  COUNTERSHAFT  GEARED  WATER  MOTOR.  A  Ye  H.  P.  Motor, 
of  more  expensive  design  than  the  ones  listed  below,  but  one  which  we  strongly  recommend  for 
the  reason  that  it  illustrates  most  effectively  not  only  the  simple  water  motor,  but  also  the  water 
motor  of  greatest  efficiency,  the  speed  of  greatest  efficiency,  the  relation  of  speed  to  water  flow, 
the  advantages  of  the  direct  drive  and  gear  drive,  and  the  application  of  the  prony  break  to  power 
generators. 

The  success  of  this  motor  depends  upon  the  following  features: 

FIRST.  The  employment  of  the  well-known  reacting  bucket-wheel  which  has  proven  by  a  series 
of  scientific  tests  to  give  the  highest  efficiency  in  a  wide  range  of  work. 

SECOND.  The  reducing  gear  which  enables  the  wheel  to  give  very  much  more  power,  the  wheel  itself 
running  at  its  normal  speed  for  greatest  efficiency. 

THIRD.  A  gear  which  is  easily  thrown  in  and  out  of  mesh  so  that  it  may  be  used  or  not,  as  desired. 

The  motor  which  we  here  offer  is  the  first  satisfactory  attempt  at  providing  a  water  motor  which  will 
give  efficient  results  under  a  wide  variety  of  conditions.  The  uses  for  such  a  motor  in  the  science 
laboratory  are  numerous,  taking  the  place  of  the  whirling  table,  supplying  small  power  for  the 
small  size  electric  generators,  the  operating  of  stirring  devices,  and  the  study  of  the  efficiency  test 
by  means  of  the  prony  break. 

This  motor  is  particularly  well  adapted  to  the  break-test  work  in  view  of  the  geared  driver,  enabling 
two  separate  and  complete  series  of  tests  to  be  made  on  the  same  instrument,  thus  offering  a  valuable 

series  of  efficiency  tests  on  both  motor  and  gears . $9.80 

38-26  THE  HARCOURT  %  H.  P.  DIRECT  DRIVE  WATER  MOTOR,  a  substantial,  attractive,  well-built 
motor  of  careful  design  and  giving  unusual  power  for  its  size.  Less  substantially  built  motors  are 
sold  in  the  hardware  trade,  but  should  not  be  confused  with  the  class  of  motor  which  we  here  offer. 

Motor  complete  with  4-inch  beveled-face  emery  wheel,  cloth  buffing  wheel,  cake  of  polish  and  the 
grooved  wooden  pulley.  Motor  and  parts  securely  packed  for  shipment  in  a  wooden  box  .  .  .  6.00 

38-26  HARCOURT  Yi  H.  P.  DIRECT  DRIVE  WATER  MOTOR,  same  as  above  described  without  accesso¬ 


ries,  but  larger  . . .  8.00 

38-27  STUD  SHAFT  to  slip  over  the  motor  shaft  of  above  motor.  This  shaft  has  the  same  threaded  end 
as  the  Ys  H.  P.  motor  shaft  and  all  the  accessories  for  this  motor  can  be  used  on  the  Yi  H.  P.  motor 
simply  by  the  addition  of  the  stud  shaft  . . .  1.26 


38-29  WATER  MOTOR  ACCESSORIES,  as  supplied  with  our  Y%  H.P.  Motor,  No.  38-26.  These  accessories 
may  be  attached  to  our  Yi  H.  P.  Motor  No.  38-26  by  means  of  above  stud  shaft.  These  accessories 
are  as  follows: 

1  Cloth  Buffing  Wheel 
1  Beveled-face  4-inch  Emery  Wheel 
1  Cake  Brass  Polish 

1  Grooved  Wooden  Pulley  Per  Set  2.00 


144 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


39-10 

39-16 


No.  39-10 


No.  39-16 


DEMONSTRATION  COMPRESSION  BIBB.  This  is  a  common  type  of  brass  commercial  hose 
bibb  cut  open  to  best  show  interior  mechanism  and  facilitate  the  demonstration  of  the  operation 

of  a  standard  faucet  of  compression  type . 

DEMONSTRATION  FULLER  BIBB,  —  cut  away  as  above  to  demonstrate  the  operation  of  a  stand¬ 
ard  faucet  of  Fuller  type . 


$1.26 

1.26 


PNEUMATICS 

ELEMENTARY  PROPERTIES  OF  MATTER 


40-10  BAROSCOPE  GLOBE  AND  BALANCE  for  demonstrating  that  air  has  weight.  This  apparatus 
consists  of  a  carefully  constructed  sensitive  balance,  to  one  arm  of  which  is  attached  a  hollow  brass 
globe,  434  inches  in  diameter;  to  the  other  a  counterpoise  weight,  exactly  balancing  the  globe  when 
filled  with  air.  This  brass  globe  is  fitted  with  stop-cock  with  male  screw,  provided  with  hook  for 
attachment  to  beam  of  the  balance. 

In  use,  the  globe  is  exhausted  by  means  of  some  efficient  air  pump.  It  is  then  attached  to  the  beam  of 
the  balance,  when  it  will  be  readily  noted  that  the  air  which  was  within  the  globe  had  weight,  inas¬ 


much  as  the  balance  is  destroyed. 

Balance  complete  with  brass  globe  and  counterpoise . $6.66 

40-16  - ,  same  as  above,  except  that  a  glass  globe  is  furnished  in  place  of  the  brass .  6.30 

40-17  BAROSCOPE  BALANCE  for  use  with  Weight  of  Air  Globe. 

This  balance  is  the  same  as  used  with  Nos.  40-10  and  40-16  except  that  no  counterpoise  is  furnished  3.76 
40-18  BAROSCOPE  GLOBE  AND  COUNTERPOISE,  of  brass  with  stop-cock  and  hook  as  used  in  No.  40-10  2.96 

40-19  - ,  of  glass  with  stop-cock  and  hook  as  used  in  No.  40-16  .  2.66 

40-22  THE  COMBINED  BAROSCOPE  GLOBE  AND  BELL  IN  VACUO,  a  glass  globe  4)4  inches  in  diam¬ 
eter  fitted  with  brass  cap  and  stop-cock  with  hook.  In  the  interior  is  a  small  bell .  6.40 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


145 


40-26  BAROSCOPE  GLOBE,  entirely  of  glass  with  hook  and  stop-cock  .  .  $2,46 

40-36  TWO-LITER  BAROSCOPE  BELL  GLASS  for  determining  the 
weight  of  air,  also  of  any  gas. 

This  consists  of  a  globe  connected  to  a  bell  glass  through  a  stop-cock.  6.46 

40-66  BAROSCOPE  BOTTLE  for  determining  the  density  of  air.  This 
consists  of  a  bottle  of  about  2-liter  capacity,  fitted  with  a  two-hole 
rubber  stopper,  glass  and  rubber  tubing  connections. 

The  proper  conduct  of  this  experiment  requires  the  use  of  an  air  pump, 
a  platform  scale  with  weights,  and  a  barometer,  as  described  in  our 
National  Physics  Course  (Experiment  M260) .  .80 

40-90  OSMOSIS  BULB  for  showing  the  diffusion  of  gases. 

This  consists  of  a  hollow  globular-shaped  vessel  with  neck,  constructed 
of  a  porous  material  which  permits  of  rapid  diffusion. 

About  70  millimeters  diameter . ,  .70 


No.  20-220 


20-200  ENDOSMOMETER  for  illustrating  the  phenomena  of  Endosmose  and  Osmose. 

The  apparatus  consists  of  a  glass  vessel  the  lower  end  of  which  is  covered  with  a  membrane,  the 
upper  end  of  which  is  connected  to  a  glass  tube  which  carries  a  scale.  This  vessel  is  supported 
so  that  the  membrane  is  held  under  solution  during  examination. 

All  parts  complete  as  illustrated  . $3.70 


20-216  STUDENTS’  OSMOSIS  APPARATUS  for  qualitative  as  well  as  quantitative 
work  in  Osmosis. 

The  apparatus  consists  of  an  Osmosis  Tube  of  design  as  illustrated,  held  ad¬ 
justably  in  a  nickel-plated  clamp  which  may  be  clamped  to  the  side  of  a  jar. 

One  end  of  the  osmosis  tube  is  closed  by  a  thin  porous  membrane  which 
may  be  removed  and  replaced  from  time  to  time  as  needed. 

Apparatus  complete  as  illustrated  .  .  . . $1.26 

20-220  OSMOTIC  PRESSURE  TUBE,  after  specifications  by  Prof.  Thomas  B.  Freas 
of  the  Department  of  Chemistry  in  Columbia  University,  for  the  rapid  il¬ 
lustration  of  the  phenomenon  of  Osmotic  Pressure. 

This  ingenious  device  consists  of  an  S.  &  S.  Diffusion  Shell  attached  to  a  glass 
chamber  which  ends  above  in  a  heavy  wall  barometer  tube  5  feet  long.  En¬ 
tering  this  chamber  is  another  tube  with  funnel  end  and  stop-cock  through 
which  the  solution  is  allowed  to  flow. 

For  rapidity  of  illustration  this  apparatus  is  not  excelled  and  the  results  ob¬ 
tained  are  very  noticeable  within  fifteen  minutes  from  the  start.  Com¬ 
plete  with  Diffusion  Shell  .  . . 3.90 


No.  20-216 


20-222  DIFFUSION  SHELL,  as  used  in  above  apparatus 


Each  .40  Per  Lot  of  10  $4.00 


146 


L.  E  .  KNOTT  APPARATUS  CO.,  BOSTON 


No.  41-60 


No.  41-20 


No.  41-71 


No.  41-70 


41-10  MERCURY  STORAGE  FUNNEL  for  storage  and  delivery  of  mercury  in  a  cleanly  condition. 

Mercury  is  stored  in  the  reservoir,  the  unclean,  lighter  and  foreign  substances  rising  to  float  as  a 
scum.  The  clean  mercury  is  delivered  from  the  bottom  by  the  pressure  of  the  piston  shown  in 
the  illustration. 

This  instrument,  some  inches  high,  will  be  found  of  the  greatest  service  in  any  laboratory  where 

clean  mercury  is  in  constant  demand . $2.00 

41-20  GAS  PRESSURE  APPARATUS  for  showing  that  the  pressure  upon  a  gas  is  transmitted  equally  in  all 


directions. 

If  slight  pressure  is  exerted  on  the  rubber  diaphragm,  this  pressure  is  communicated  equally  to  the 
open  ends  of  each  of  the  five  manometers. 

Complete  as  illustrated .  6.80 

41-40  HALL'S  FRICTION  OF  AER  APPARATUS,  designed  by  Professor  E.  H.  Hall  of  Harvard  Univer¬ 
sity  for  showing  very  clearly  the  relative  friction  of  air  passing  through  long  and  short  pipes.  Com¬ 
plete  as  illustrated,  including  rubber  tubing  and  mouthpiece  .  . .  2.90 

41-60  PRESSURE  GAUGE  for  steam  or  air  pressure.  Enclosed  in  iron  case  with  nickel-plated  ring,  diameter 

of  dial  3  inches,  for  pressures  up  to  150  pounds .  3.76 

41-66  VACUUM  GAUGE,  same  quality  as  above,  tested  and  graduated  to  read  a  vacuum  from  0  to  30  inches 

of  mercury.  Enclosed  in  iron  case  with  nickel-plated  ring,  diameter  of  dial  3  inches .  3.60 


41-70  DEMONSTRATION  PRESSURE  AND  VACUUM  GAUGE  with  silvered  metal  graduated  scale; 

highest  quality,  glass  front  permitting  full  view  of  the  mechanism.  May  be  used  under  a  bell 
glass  or  connected  directly  by  tubing  to  a  pressure  or  vacuum  chamber.  Diameter  5  inches;  grad¬ 
uated  to  read  0-75  pounds  per  square  inch  (approximately  150  pounds  pressure)  and  0-30  inches  9.60 

41-71  DEMONSTRATION  BOURDON  GAUGE.  The  essential  features  of  the  Bourdon  Gauge  mounted  so 

that  its  working  mechanism  is  instantly  understood.  Mounted  as  illustrated .  2.90 

41-72  COMBINATION  PRESSURE  AND  VACUUM  GAUGE,  enclosed  in  iron  case.  Reads  0-75  pounds 

per  square  inch  and  0-30  inches . .  6.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


147 


No.  41-100  No.  41-105  No.  41-110 

41-100  BOYLE’S  LAW  APPARATUS  for  the  accurate  determination  of  Boyle’s  Law  up  to  ten  atmos¬ 
pheres  of  pressure. 

This  apparatus  consists  of  a  frame  mounted  on  an  upright  support.  This  frame  holds  a  sensitive 
manometer  with  a  carefully  graduated  scale  with  clear  and  distinct  graduations  and  figures. 

The  pressure  is  introduced  through  the  stop-cock  shown  at  the  left  and  indicated  by  the  small  pressure 
gauge  shown  at  the  top. 

This  instrument  is  handsomely  finished,  occupies  but  little  space,  being  but  1  meter  high,  and  is 


capable  of  very  accurate  determinations . $24.60 

41-106  ADJUSTABLE  SCALE  BOYLE’S  LAW  APPARATUS,  after  Crew  and  Tatnall’s  “Laboratory 
Manual  of  Physics,”  Exercise  37,  for  determining  Boyle’s  Law  of  pressures  ranging  between  one- 
half  and  two  atmospheres .  4.96 

41-106  COMPRESSION  PUMP,  especially  adapted  for  use  with  above . 26 


HAND  AIR  PUMP,  recommended  for  use  with  No.  41-106  Boyle’s  Law  Apparatus.  For  description 
and  illustration,  see  Section  42. 

41-110  FIVE-FOOT  ADJUSTABLE  BOYLE’S  LAW  APPARATUS  for  the  determination  of  Boyle’s  Law. 

The  apparatus  consists  of  a  metal  frame  with  scale  mounted  on  our  H  Base,  the  tube  carriers  consist¬ 
ing  of  wooden  strips  attached  to  special  clamps  in  such  a  way  that  there  is  a  perfect  alignment 
at  all  times  relative  to  the  scale.  Each  tube  is  provided  with  a  movable  brass  indicator  for  regis¬ 
tering  the  heights  of  the  columns  of  mercury.  Instead  of  the  tube  with  the  closed  end,  we  are 
supplying  a  tube  closed  with  an  air-tight  glass  stop-cock.  This  apparatus  stands  some  150  centi-  . 
meters  high,  and  being  mounted  on  our  special  design  H  Base,  is  extremely  rigid.  It  is  hand¬ 
somely  finished  in  japan  and  nickel-plate. 

Complete  as  illustrated . .  .• .  9.00 


148 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  41-113 


BOSTON 


41-113  KNOTT’S  ADJUSTABLE  SCALE  BOYLE’S  LAW  AND  BAROMETER  APPARATUS  for  deter¬ 
mining  Boyle’s  Law. 

This  form  of  apparatus  consists  of  Miller’s  Pressure  Tube  mounted  on  Adjustable  Scale  Support 
as  described  in  the  following  item,  No.  41-115.  The  use  of  this  apparatus  requires  some  efficient 


form  of  Air  Pump.  No.  42-76  is  highly  recommended. 

Complete  as  illustrated,  with  stand . $3.85 

41-114  MILLER’S  COMBINATION  PRESSURE  GAUGE,  tube  only  unmounted .  2.00 


41-116  SIMPLE  ADJUSTABLE  SCALE  BOYLE’S  LAW  APPARATUS  for  the  derivation  of  the  law  that 

the  product  of  the  Volume  of  a  Gas  by  its  pressure  is  a  constant  quantity. 

In  this,  our  new  form,  we  have  striven  to  correct  mistakes  of  old  types  and  enhance  the  value  of  an 
inexpensive  Boyle’s  Law  Stand.  Our  stand  consists  of  a  finished  hardwood  backing  attached 
to  a  casting,  which,  in  turn,  is  threaded  into  a  neatly  finished  tripod  base.  Our  improvement  obvi¬ 
ates  the  use  of  cumbersome  clips,  rubber  bands,  etc.  The  tube  may  be  attached  or  removed  in  an 
instant  from  the  above-mentioned  wooden  back,  one  sliding  brass  clip,  which  also  answers  the 


purpose  of  an  indicator,  being  the  only  fastening  device. 

Complete  with  simple  J  tube,  as  illustrated .  2.95 

41-116  ADJUSTABLE  SCALE  BOYLE’S  LAW  STAND.  Stand  only,  as  used  in  above .  1.96 

41-120  EXTRA  HEAVY  BOYLE’S  LAW  TUBE,  simple  J  form,  as  used  in  No.  41-116 .  1.00 

41-126  BOYLE’S  LAW  TUBE,  unfilled,  after  Millikan,  Gale  and  Bishop  (Experiment  9)  .33 

41-130  TRIPOD,  ROD,  UNIVERSAL  CLAMP  AND  HOLDER  after  Millikan,  Gale  and  Bishop 

(Experiments  6,  etc.) .  1.95 

41-155  HEAVY  WALLED  BAROMETER  TUBE,  heavy  walled  glass  tube  80  centimeters  long,  closed  at 

one  end .  .26 

41-167  - ,  graduated,  for  use  when  quantitative  measurements  are  desired.  This  tube  is  graduated 

•  throughout  the  entire  length  to  millimeters  from  zero  at  the  open  end  of  the  tube .  2.00 

41-160  GILLEY  IMPROVED  FORM  MERCURY  WELL . 22 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


149 


AIR  PUMPS 

VACUUM  PUMPS  COMPRESSORS  ASPIRATORS 

THE  RITCHIE  PUMPS 
Nos.  42-10  and  42-16 

(See  next  page) 

With  the  many  vast  improvements  which  have,  in  the  past  few  years,  been  made  in  oil-sealed 
pumps,  the  question  may  reasonably  be  asked  why  we  continue  to  make  the  Ritchie  Pumps. 

The  answer  is  clear  when  we  consider  that  the  most  minute  details  of  construction  have  been 
worked  out  through  years  of  experience  and  the  manufacturer  is,  therefore,  no  longer  in  doubt 
as  to  the  correct  weight  and  kind  of  material  to  use  in  the  valve  and  other  essential  parts,  the  form 
of  the  valve  seat  and  method  of  grinding  which  will  give  the  best  results.  Such  matters  of  detail 
as  the  fitting  of  the  plunger,  the  grinding  of  all  internal  parts,  and  a  multitude  of  other  points  which 
must  be  carefully  worked  out  in  order  to  make  sure  that  a  pump  will  give  permanent  satisfaction, 
have  been  reduced  to  definite  manufacturing  terms,  with  the  result  that  we  are  able  to  produce, 
at  a  definite  price,  an  instrument  in  which  we  can  guarantee  a  high  degree  of  efficiency. 

Considering  all  the  conditions,  we  believe  we  are  justified  in  claiming  that  the  Ritchie  type 
of  pump  is  worthy  of  your  most  careful  consideration.  Please  note  that  it  requires  less  attention 
in  use;  that  it  gives  a  sufficiently  high  degree  of  vacuum  for  all  practical  laboratory  purposes;  that 
it  may  be  absolutely  relied  upon  and  that  no  experience  nor  special  precautions  are  required  in  its 
use. 


THE  INSTITUTE  OIL-SEALED  HIGH  VACUUM  PUMPS 
Nos.  42-20  and  42-25 

(See  next  page) 

For  work  requiring  the  highest  vacuum,  the  oil-sealed  pump  has  been  very  generally  recognized. 
The  defects  as  well  as  the  strong  points  of  the  old  form  of  oil  pump  have  been  very  carefully  studied 
during  the  past  two  years,  with  the  result  that  we  are  able  to  offer  a  pump  in  which  the  defects  of 
the  older  pumps  have  been  entirely  eliminated.  Our  new  type  is  rapid  in  action  and  guaranteed 
not  to  squirt  oil  from  the  cylinder.  This  latter  difficulty  has  been  common  heretofore  in  practically 
all  of  the  oil  pumps  on  the  market.  Our  pump  is  also  capable  of  an  extraordinarily  high  degree  of 
vacuum. 

TESTS.  The  test  which  we  have  found  most  practical  is  the  electrical  discharge  in  the  ex¬ 
hausted  chamber,  and  no  pump  passes  our  inspection  department  until  it  has  produced  a  satis¬ 
factory  X-Ray  vacuum. 

OPERATION.  The  operating  part  consists  of  a  substantial  metal  cylinder  alternately  raised 
and  lowered  into  a  fluid  chamber  filled  with  oil  of  the  lowest  possible  vapor  tension.  This  action 
results  in  a  Torricellian  vacuum  being  produced  in  the  cylinder  at  each  stroke.  At  the  proper 
place  in  the  stroke  the  air  is  allowed  to  flow  from  the  chamber  being  exhausted  into  the  cylinder, 
and  the  operation  is  thus  continued. 

It  will  be  noted  that  we  obtain  in  a  single  cylinder  all  the  advantages  of  two  cylinders  in  tan¬ 
dem  frequently  used  by  manufacturers  of  oil  pumps.  This  is  made  possible  from  the  fact  that 
air  taken  from  the  lower  side  of  the  cylinder  to  produce  the  Torricellian  vacuum  in  the  lower  cham¬ 
ber  is  forced  into  the  upper  chamber,  from  which  it  is  in  turn  expelled,  a  Torricellian  vacuum  be¬ 
ing  formed  in  the  upper  portion  of  the  chamber. 

It  will  thus  be  seen  that  the  degree  of  vacuum  depends  upon  the  vapor  tension  of  the  fluid 
used. 

CONSTRUCTION.  The  simplicity  of  design  enables  all  parts  to  be  of  most  substantial 
construction.  The  absence  of  delicate  valves  to  become  worn  and  thrown  out  of  adjustment  in¬ 
sures  the  continued  operation  of  the  pump  and  its  dependable  qualities. 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


150 


42-10 


42-15 


No.  42-15 


THE  RITCHIE  PUMPS 

(For  description  see  previous  page) 


THE  RITCHIE  STANDARD  PUMP,  cylinder 

2J4  inches,  stroke  7  inches,  plate  10  inches  ' .  .  $33.25 


THE  RITCHIE  SUPERIOR  PUMP,  same  as 
above,  except  that  the  plate  is  equipped  with 
insulated  binding  posts  as  illustrated  ....  35.50 


THE  INSTITUTE  OIL-SEALED  PUMPS 

(For  description  see  previous  page) 


No.  42-20 


42-20  INSTITUTE  OIL-SEALED  PUMP  “A,”  cylinder  234  inches,  stroke  5  inches,  plate  10  inches  .  .  $26.80 
42-25  INSTITUTE  OIL-SEALED  PUMP  “B,”  cylinder  234  inches,  stroke  8  inches,  plate  10  inches  .  .  45.00 

42-45  TORRENTIUM  OIL  FOR  HIGH  VACUUM  WORK.  For  the  best  results  with  oil-sealed  pumps, 
especially  prepared  oil  having  both  the  right  viscosity  and  vapor  tension  is  required.  To  meet  the 
requirements  of  our  own  Institute  Pumps  as  well  as  for  all  oil-sealed  pumps,  we  have  arranged 
to  have  supplied  to  us  a  special  oil  prepared  to  meet  the  most  exacting  demands  of  high  vacuum 
work. 

The  price  is  of  necessity  somewhat  higher  than  for  oils  of  commercial  grade,  but  the  amount  required 

for  each  pump  is  so  small  that  the  expense  is  nominal . .  Per  Quart  1.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


151 


42-75  CONDENSING  AND  EXHAUSTING  HAND  AIR  PUMP 
WITH  SWIVEL  for  general  utility  in  laboratory  practise  where 
a  relatively  low  vacuum  or  pressure  is  desired. 

This  is  a  simple  pump  with  valve  for  both  compression  and  ex¬ 
haustion  and  has  a  cylinder  1  inch  in  diameter  by  113^  inch 
stroke.  The  lower  end  is  drilled  and  tapped  to  receive  our 
air  pump  attachment  which,  in  use,  requires  No.  6-1000  Uni¬ 
versal  T-beam  Basic  Clamp  “A.”  This  pump  attachment  is 
made  in  two  parts  and  held  together  by  a  friction  joint  which 
allows  the  setting  of  the  pump  to  any  angle  in  one  plane. 

It  is  provided  with  a  nickel-plated  T-screw  for  securing  to  the 
Basic  Clamp. 

Complete  as  illustrated,  without  Basic  Clamp . $4.00 


42-76  - ,  similar  to  above,  but  with  attached  Clamp 


3.60 


42-80  AIR  PUMP  PLATE,  diameter  10  inches,  vent  hole  tapped  for  all  air  pump  accessories,  surface  turned 
true  and  carefully  ground  plane.  Mounted  on  substantial  tripod  base  and  provided  with  guard 
plug  and  stop-cock .  4.90 


42-82  TEN-INCH  HEAVY  GROUND  GLASS  PUMP  PLATE.  The 

plate  consists  of  ground  glass  plate  which  is  firmly  cemented  to 
a  low  form  of  special  tripod  base.  The  base  is  cast  in  one  piece 
to  obviate  danger  of  leakage.  It  is  provided  with  brass  stop¬ 
cock  and  brass  connecting  tube  with  oil-sealed  taps  for  inlet 
of  air,  and  manometer . $9.35 


42-100  BOLTWOOD  MERCURY  PUMP,  an  inexpensive  automatic 
mercury  pump  requiring  only  a  small  amount  of  mercury. 

This  pump  is  practically  automatic  in  its  action  and  is  con¬ 
tinuously  operated  by  a  small  aspirator.  It  is  rapid  in  action 
and  will  exhaust  a  liter  flask  sufficient  for  any  ordinary  work 


in  twenty  minutes. 

Mounted  on  neat  wooden  stand . 11.25 

42-102  - ,  same  as  above,  without  stand .  9.00 


No.  42-100 


152 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


42-110  ROTARY  COMPRESSOR  OR 
VACUUM  PUMP,  capacity  15 
cubic  inches  per  revolution. 

Pulleys,  6  inches  in  diameter, 

2-inch  face. 

The  idea  of  these  rotary  pumps 
is  comparatively  new,  and, 
from  their  construction,  are  de¬ 
signed  to  fulfil  all  the  usual  re¬ 
quirements  of  a  compressor  or  a 
vacuum  pump.  For  many  pur¬ 
poses  they  are  unexcelled.  Be¬ 
sides  presenting  a  mechanical 
and  handsome  appearance, 
these  pumps  have  the  follow¬ 
ing  features  which  are  highly 
recommended. 

The  in-take  and  delivery  of  air  is 
continuous  and  does  not  depend 
upon  valves  or  springs  of  any 
form. 

The  simplicity  and  facility  with 
which  they  may  be  set  up  and 
operated. 

The  small  floor  space  and  the  light 
power  required. 

The  positive  lubrication  secured 
by  simple  automatic  lubricator. 

The  efficient  cooling  by  special 
water  jackets. 

The  high  degree  of  efficiency 
possible: — a  pressure  capacity 
of  25  to  30  pounds  per  square 
inch  when  used  as  a  compres¬ 
sor;  as  a  vacuum  pump,  main- 
No.  42-110  taining  most  any  vacuum  pos¬ 

sible,  under  local  conditions 
of  the  atmosphere,  up  to  90 
per  cent . $56.00 


42-130  HARCOURT  ELECTRIC  COMPRESSED  AIR  OUT¬ 
FIT.  Consists  of  an  electric  air  compressor  connected 
to  and  mounted  on  same  base  as  the  storage  tank. 

The  Electric  Air  Compressor  runs  from  any  110-Volt 
socket  A.  C.  or  D.  C.,  has  no  exposed  electrical  parts, 
gearing,  chains,  belts,  rods,  shafts  or  levers.  Is 
guaranteed  to  develop  100  pounds  air  pressure  with¬ 
out  overheating. 

Under  actual  laboratory  tests  this  compressor  filled 
the  5-gallon  tank  in  four  minutes  with  air  at  60  pounds 
pressure,  which  pressure  was  increased  to  70  pounds 
in  five  minutes,  80  pounds  in  six  minutes  and  90 
pounds  in  seven  and  one-half  minutes. 

Current  consumption  160  watts. 

Storage  Tank  is  a  5-gallon  galvanized  iron  tank,  guar¬ 
anteed  air-tight  and  provided  with  all  necessary  cocks 
and  pressure  gauge. 

Complete  as  illustrated,  with  electric  cord,  and  at¬ 
tachment  plug . $69.50 


No.  42-130 


42-135  COMPRESSED  AER  pUTFIT  WITH  HAND  COMPRESSION  PUMP.  Similar  in  general  struc¬ 
ture  to  above,  but  with  Compound  Lever  Compression  Pump  in  place  of  the  Electric  Air  Compres¬ 
sor. 

Cylinder  3J4  inches,  stroke  5^  inches,  displacement  per  stroke  45.6  cubic  inches,  working  pressure 
about  one  hundred  pounds. 

With  this  outfit  pressures  up  to  40  pounds  can  be  readily  secured. 

Pump,  Tank  with  necessary  cocks  and  Pressure  Gauge  all  connected  and  mounted  on  substantial 
base  . 


$36.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


153 


Nos.  42-150  and  42-160 


Nos.  42-162, 
42-162,  and 
42-177 


Nos.  42-153,  42-163,  and  42-178 


No.  42-175 


No.  42-190 


42-160  CHAPMAN’S  ASPIRATOR  for  reduction  of  air  pressure  by  water  aspiration. 

This  aspirator  is  of  brass,  4  inches  long,  inch  I.  P.  size  thread,  giving  a  capacity  of  5  cubic  feet 

per  hour . $1.45 

42-162  HYDRANT  COUPLING  for  use  in  connecting  our  No.  42-150  to  %-inch  hose  faucet .  .30 

42-153  HYDRANT  COUPLING  for  connecting  our  No.  42-150  to  a  smooth  faucet.  These  couplings  cannot 

leak  or  be  forced  off .  .50 

42-160  CHAPMAN’S  ASPIRATOR,  similar  to  No.  42-150,  but  with  capacity  of  18  cubic  feet  per  hour. 

Length  5  inches;  inch  I.  P.  size  thread .  1.96 

42-162  HYDRANT  COUPLING  for  use  in  connecting  our  No.  42-160  to  %-inch  hose  faucet .  .30 

42-163  HYDRANT  COUPLING  for  use  in  connecting  our  No.  42-160  to  a  smooth  faucet.  These 

couplings  cannot  leak  or  be  forced  off .  .60 

42-176  RICHARD’S  ASPIRATOR,  a  more  powerful  and  efficient  filter  pump  than  Nos.  42-150  and 

42-160.  Length  7  inches;  %  inch  I.  P.  size  thread .  1.80 


42-177  HYDRANT  COUPLING  for  use  in  connecting  our  No.  42-176  to 
%-inch  hose  faucet . 

42-178  HYDRANT  COUPLING  for  use  in  connecting  our  No.  42-176  to  a 
smooth  faucet.  These  couplings  cannot  leak  or  be  forced  off  .  . 

42-190  MUENCKE’S  ASPIRATOR,  entirely  of  glass,  total  length  inches. 

As  all  parts  are  visible,  this  is  a  convenient  demonstration  instrument 

42- 200  ASPIRATOR  DEMONSTRATION  TUBES  after  Hall  No.  XLVII.  Pair 

HIGH  PRESSURE  AIR  STORAGE  TANKS  for  the  storage  of  air  or  non- 
corrosive  gases  under  pressure.  These  tanks  are  made  of  heavy  galvanized  iron 
and  guaranteed  to  be  absolutely  air-tight,  under  a  guarantee  test  of  150  pounds 
and  for  a  working  pressure  of  100  pounds. 

43- 110  AIR  STORAGE  TANK,  capacity  2lA  gallons,  size  6  inches  diameter  by 

20  inches  high . 

43-111  - ,  capacity  5  gallons,  size  9  inches  diameter  by  20  inches  high  .  . 

43-112  - ,  capacity  12  gallons,  size  10  inches  diameter  by  33  inches  high  . 

PRESSURE  GAUGE.  See  No.  41-60 


Nos.  43-110  to  43-112 


154 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


BELL  GLASSES 


CLEAR,  WHITE  GLASS,  FLANGES  GROUND  AND  TESTED 


Nos.  43-25  to  43-27 
♦ 


Nos.  43-66  to  43-67 


No.  43-70 


No.  43-60 


No.  43-75 


No.  43-80 


43-26  STRAIGHT  FORM  BELL  GLASS,  WITH  KNOB  TOP.  Capacity  1  gallon,  inside  height  11 

inches,  diameter  6  inches . 

43-27  -  — ,  same  as  above,  capacity  2  gallons,  inside  height  15  inches,  diameter  7  inches . 

43-35  SWELLED  FORM  BELL  GLASS,  WITH  KNOB  TOP.  Capacity  2  gallons,  inside  height  12 
inches,  diameter  7  inches . . . * 

43-37  -  — ,  same  as  above,  capacity  3  gallons,  inside  height  13  inches,  diameter  inches . 

43-40  -  — ,  same  as  above,  capacity  5  gallons,  inside  height  15  inches,  diameter  10  inches . 

43-50  STRAIGHT  FORM  BELL  GLASS,  WITH  GLASS  STOPPER.  Capacity  1  gallon,  inside  height 

11  inches,  diameter  6  inches . 

43-60  STRAIGHT  FORM  BELL  GLASS,  NECK  FOR  CORK  STOPPER.  Capacity  1  gallon,  inside  height 
11  inches,  diameter  6%  inches . 

43-65  LOW  FORM  BELL  GLASS,  WITH  KNOB  TOP.  Inside  height  2^  inches,  diameter  4  inches  .  . 

43-67  -  — ,  same  as  above,  inside  height  4  inches,  diameter  6  inches . *.  .  . 

43-70  HAND  AND  BLADDER  GLASS,  swelled  form,  both  flanges  ground  and  tested,  medium  size  .  .  . 

43-76  BELL  GLASS,  special  mold,  ground  flange,  re-enforced  neck  for  our  No.  30  rubber  stopper.  Inside 
height  4  inches.  This  bell  glass  is  used  with  a  one-hole  rubber  stopper  and  a  barometer  tube  to 
perform  the  experiment  of  No.  43-80  . 

43-80  BELL  GLASS,  straight  sides,  about  3  feet  high,  flange  ground  and  tested  for  use  with  No.  41-156  Ba¬ 
rometer  Tube  and  No.  41-160  Well,  to  show  successive  diminution  in  pressure  when  placed  on  the 
plate  of  an  air  pump. 

Complete  as  illustrated,  with  Barometer  Tube  and  Well . 

43-82  BELL  GLASS  only,  of  above . 


$1.45 

2.20 

1.95 

2.90 

6.30 

1.76 

1.45 

.65 

1.00 

1.00 

1.25 

4.25 
3.75 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


155 


43-140  MANOMETER  for  attachment  to  air  pump  to  denote  degree  of  exhaustion. 

This  is  an  instrument  carefully  constructed  and  handsomely  finished  for  attachment  to  the  guard  or 
vent  hole  to  denote  the  degree  of  exhaustion.  It  consists  of  a  metal  casting,  threaded  to  fit  any 
hole  threaded  by  16.  Attached  to  this  casting  is  a  black  oxidized  metal  scale  filled  in  white, 
holding  a  manometer  tube.  This  scale  and  tube  are  encased  in  a  heavy  glass  cover. 

This  instrument  will  be  found  efficient,  rapid,  and  a  valuable  accessory  in  the  study  of  Pneumatics  .  $6.45 

43-146  MOVABLE  SCALE  MANOMETER,  mounted  on  neat  wooden  support  stand,  to  determine  the  degree 


of  exhaustion  in  experiments  in  Pneumatics. 

This  is  an  improved  form  of  manometer  with  glass  stop-cock  which  is  mounted  with  a  movable  scale 

support  supporting  the  mirror  glass  scale  on  a  neatly  finished  wooden  stand  .  6.26 

43-160  SIMPLE  MANOMETER,  consisting  of  a  U-tube  mounted  with  scale  on  a  neatly  finished  wooden 

stand  .  1.70 


No.  41-113 


43-160  JAR  WITH  TWO  MANOMETER  TUBES,  IN¬ 
LET  TUBE  and  PINCH-COCK,  after  Milli¬ 
kan,  Gale  and  Bishop  (Experiment  5)  ...  .  $1.25 


43-161  MANOMETER  TUBE  only . 40 

43-165  BALANCING  COLUMNS  TUBE,  after  Millikan, 

Gale  and  Bishop  (Experiment  5) .  .85 


41-113  MILLER’S  COMBINATION  PRESSURE 
GAUGE,  for  registering  high  pressures. 

This  is  a  tube,  1  meter  in  height.  Our  illustration 
shows  it  mounted  on  our  No.  41-116  Boyle’s 
Law  stand.  One  arm  of  this  tube  is  provided 
with  a  stop-cock  so  that  the  instrument  may 
be  used  as  a  Boyle’s  Law  Tube  as  well  as  a  ba¬ 
rometer.  In  use  as  a  pressure  tube,  however, 
this  stop-cock  must  be  left  open.  In  use  as  a 
Barometer,  the  stop-cock  is  left  open  until  the 
tube  has  been  completely  filled,  when  it  is 
closed.  The  mercury  will  then  fall  to  the 
point  of  barometric  height.  Complete  as  il¬ 


lustrated,  with  stand .  3.85 

41-114  MILLER’S  COMBINATION  PRESSURE 

GAUGE.  Tube  only,  unmounted .  2.00 

43-170  PRESSURE  GAUGE,  as  designed  by  Messrs. 

Turner  and  Hersey. 


This  gauge  has  been  especially  designed  for  regis¬ 
tering  high  pressures,  the  length  facilitating 
this  use.  It  must  be  used,  however,  on  some 
form  of  stand.  Our  illustration  shows  it  in 
use  mounted  on  our  No.  41-116,  a  description 


of  which  will  be  found  under  No.  41-115. 

Complete  as  illustrated,  with  stand .  3.30 

43-171  PRESSURE  GAUGE.  Tube  only,  unmounted  .  1.35 


No.  43-170 


156  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  43-200 


No.  43-202 


No.  43-206 


No.  43-240 


No.  43-246 


No.  43-247 


No.  43-260 


No.  43-204 


43-200  BRASS  COUPLING,  threaded  to  fit  our  air  pumps  and  air  pump  accessories . $0.33 

43-202  BRASS  STOP-COCK,  double  male  screw,  threaded  to  fit  our  air  pumps  and  air  pump  accessories; 

inch  bore .  .66 

43-204  BRASS  NIPPLE,  female  screw,  threaded  to  fit  No.  43-202  Stop-cock  or  No.  43-200  Coupling,  or  any 

of  our  air  pumps  and  air  pump  accessories .  .33 

43-206  BRASS  GUARD  PLUG,  threaded  to  fit  our  air  pumps  .  '. .  .33 

43-207  BRASS  T-GUARD  PLUG  threaded  to  fit  our  air  pumps .  .43 

43-210  PUMP  OIL  AND  CAN.  This  combination  will  recommend  itself  to  many  teachers  who  require 

an  efficient  lubricator.  Four-ounce  size  with  screw  stopper.  Filled .  .36 

43-216  PHOSPHORUS  PENTOXEDE  for  absorption  of  moisture  in  high-vacuum  experiments.  Sealed 

bottle,  containing  1  ounce .  .66 

43-217  VACUUM  TUBING.  This  is  a  specially  prepared  heavy-walled  reinforced  rubber  tubing,  %  inch 

diameter,  obviating  leakage  in  making  air-tight  connections . Per  Foot  .20 


43-220  RUBBER  DAM  OR  THIN  RUBBER  SHEETING,  especially  useful  in  illustrating  the  crushing 

force  of  atmospheric  pressure . Per  Square  Foot  .33 

43-221  VEGETABLE  PARCHMENT,  good  quality,  adapted  for  demonstrating  the  crushing  force  of  at¬ 
mospheric  pressure . Per  Sheet  .10 

43-222  ANIMAL  PARCHMENT,  good  quality . Per  Square  Foot  .60 

43-226  LEATHER  WASHERS  for  use  with  stop-cocks,  plugs,  etc.,  %  inch  diameter  by  %  inch  hole. 

Per  Dozen  .26 

43-230  RUBBER  BAG  for  experiments  in  pneumatics.  This  bag  is  of  light  rubber  of  the  best  quality  and 

is  furnished  complete  with  outlet  tube  and  screw  pinch-cock .  1.16 

43-240  FOUNTAIN  IN  VACUO,  illustrating  atmospheric  pressure.  In  use,  the  tripod  is  removed  and  the 
apparatus  is  screwed  to  the  center  of  the  pump  plate.  The  stop-cock  is  then  turned  and  air  ex¬ 
hausted  from  the  vessel.  If  the  apparatus  is  again  mounted  on  the  tripod  and  placed  in  a 
dish  of  water  the  pressure  of  the  atmosphere  will  force  the  water  into  the  vessel  showing  a  very 
vigorous  fountain  as  soon  as  the  stop-cock  is  opened. 

Complete  as  illustrated .  6.60 

43-246  DEMONSTRATION  SIXTEEN-INCH  WATER  HAMMER  for  showing  that  water  or  any  liquid  will 

fall  as  a  solid  in  a  vacuum. 

In  use,  the  air  is  exhausted  from  the  tube  and  the  end  held  under  water  and  stop-cock  opened.  Water 
is  allowed  to  be  forced  by  atmospheric  pressure  until  about  full-  If  tube  is  now  inverted,  the 
water  will  fall  as  a  solid  mass,  the  tube  emitting  a  distinct  sound  as  if  struck  by  a  blow .  2.80 

43-247  WATER  HAMMER,  illustrating  that  water  will  fall  as  a  solid  in  vacuo.  This  consists  of  a  tube, 

30  centimeters  in  length,  partially  filled  with  water  in  a  vacuum.  With  one  bulb .  .66 

43-260  TWO-BULB  MUSICAL  WATER  HAMMER,  arranged  so  that  the  water  falling  in  vacuo  will  emit 

pleasing  tones  in  addition  to  the  metallic  click .  1.10 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


157 


No.  43-265 


Nos.  43-276  and  43-277 


No.  34—40 


No.  43-270 


43-266  MAGDEBURG  HEMISPHERES  for  demonstrating  atmospheric  pressure  in  all  directions. 

The  apparatus  consists  of  two  cast,  hollow  hemispheres  of  meta^  the  edges  of  which  are  carefully 
ground  smooth  to  make  an  air-tight  junction.  On  one  is  cast  a  “boss”  which  is  tapped  for  a  brass 
stop-cock  threaded  to  fit  the  air  pump  and  also  the  tripod  illustrated.  Each  hemisphere  is  pro¬ 
vided  with  convenient  handles.  The  whole  is  durably  and  handsomely  finished . $3.96 

34-40  SEVEN-IN-ONE  APPARATUS  OR  SPIROMETER,  GAGE’S  IMPROVED  for  demonstrating 
fundamental  principles  in  pneumatics  and  hydraulics. 

This  apparatus  consists  of  a  seamless  brass  cylinder  6  inches  in  diameter,  mounted  on  a  metal  cast¬ 
ing,  provided  with  bosses,  into  which  rods  may  be  screwed  from  either  side.  The  cylinder  is  pro¬ 
vided  with  an  ingeniously  designed  piston  which,  owing  to  its  construction,  has  greater  efficiency 
the  longer  the  use.  This  construction  also  obviates  the  sticking  of  the  washers  and  leakage  around 
them.  Each  instrument  is  provided  with  our  detachable  handle  in  the  piston  head,  a  fixed  han¬ 
dle  with  brass  stop-cock  with  nipple,  a  rubber  tube,  and  funnel.  This  apparatus,  as  implied 
from  the  name  “Seven-in-One,”  will  illustrate  the  principles  involved  in  seven  different  instru¬ 
ments,  as  follows:  —  Hydraulic  Lift,  Hydraulic  Press,  Incompressibility  of  Liquids  Apparatus, 
Pascal’s  Law  Apparatus,  Pneumatic  Lift,  Hydrostatic  Bellows,  Magdeburg  Hemispheres. 

This  instrument  is  handsomely  finished  in  nickel  plate  and  is  furnished  complete  with  three  nickel- 
plated  rods .  8.90 

43-270  MODEL  OF  A  DIVING  BELL,  demonstrating  how,  in  a  caisson,  air  is  supplied  to  keep  up  life  and  to 
keep  back  the  water. 

The  design  above  illustrated  demonstrates,  in  a  simple  way,  the  principle  of  caissons.  A  conical¬ 
shaped  glass  vessel  with  meta  mountings  top  and  bottom  has,  at  its  top,  a  tube  for  supply  of  air 
which  is  forced  into  the  vessel  by  means  of  an  air  pump.  The  bottom  casting  is  designed  to  hold 
a  slow-match  as  well  as  to  support  a  weight.  The  whole  is  submerged  in  a  jar  of  water  as  illus¬ 
trated.  The  supply  of  fresh  air  through  the  tube  keeps  the  spark  on  the  slow-match  alive.  The 
whole  is  suspended  in  the  jar  by  any  convenient  means. 

Diving  Bell  complete  with  weight,  slow-match  and  special  jar .  6.76 

43-276  BURSTING  SQUARES.  When  placed  under  a  bell  glass  on  a  pump  plate  and  the  air  exhausted 
from  under  the  bell  glass  the  expansive  force  of  the  air  in  the  bursting  square  will  burst  the  square 
with  great  violence.  (See  Protecting  Shield  No.  43-277) . Per  Dozen  2.16 

43-277  WIRE  GUARD  for  use  under  a  bell  glass  to  protect  the  bell  glass  from  flying  broken  parts  of  the 

bursting  squares . Each  .46 


158 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  43-285  No.  43-290 


BELL  IN  VACUO  APPARATUS,  illustrating  non-transmis¬ 
sion  of  sound  in  a  vacuum. 

This  apparatus  consists  of  a  large-sized  bell  jar  with  brass 
cap,  through  the  center  of  which  slides  a  brass  rod  gripped 
air-tight  by  means  of  a  packing  screw.  A  bell  suspended 
by  a  horizontal  axis  in  a  stirrup  is  supported  over  the  vent 
in  the  center  of  the  pump  plate.  This  bell  is  rung  by  tip¬ 
ping  through  the  agency  of  the  sliding  rod. 

When  placed  on  pump  plate,  as  illustrated,  if  air  is  not  ex¬ 
hausted,  the  bell,  if  tipped,  will  emit  a  distinct  tone.  If, 
however,  the  air  is  exhausted,  the  sound,  though  not  abso¬ 
lutely  lost,  will  be  diminished  to  such  an  extent  as  to  readi¬ 
ly  illustrate  the  non-transmission  of  sound  in  a  vacuum. 


Complete  as  illustrated,  with  BelTand  Stirrup  and  Bell  Glass  with  Sliding  Rod.  All  brass  parts 

polished  and  lacquered . ; . $6.80 


43-282  BELL  IN  STIRRUP,  as  illustrated  above 


2.80 


43-283  BELL  GLASS  WITH  SLIDING  ROD,  as  illustrated  above 


4.00 


43-285  BELL  IN  VACUO,  illustrating  non-transmission  of  sound  in  a  vacuum. 

This  is  a  self-contained  instrument  supplied  with  a  small  nickel-plated  bell  suspended  by  springs  to 
brass  binding  posts  which  are  sealed  into  the  top  of  a  medium-sized  bell  glass.  As  the  flange  of  this 
bell  glass  is  carefully  ground  and  tested  and  the  vibration  of  the  bell  is  deadened  by  suspending 
on  springs,  the  non-transmission  of  sound  is  quite  noticeable,  the  tone  being  almost  lost  in  the 
vacuum. 

Complete  as  illustrated .  2.90 

43-290  MOUNTED  ELECTRIC  BELL  for  use  in  connection  with  a  bell  glass  and  with  our  No.  42-16  Air 
Pump  with  electrical  connections,  to  illustrate  non-transmission  of  sound  in  a  vacuum 


Mounted  as  illustrated  on  neatly  polished  wooden  upright .  1.60 

43-26  BELL  GLASS,  straight  form,  with  knob  top,  11  inches  high  by  6  inches  diameter .  1,46 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


159 


No.  40-22  No.  43-310 


40-22  BELL  IN  BAROSCOPE  GLOBE  for  the  illustration  of  non-transmission  of  sound  in  a  vacuum;  also 
used  to  demonstrate  the  fact  that  air  has  weight. 

This  is  a  glass  globe,  4J4  inches  in  diameter,  fitted  with  brass  cap  and  a  stop-cock  with  hook,  and 
has  in  its  interior  a  small  bell. 

To  demonstrate  that  air  has  weight,  this  globe  is  used  as  an  ordinary  baroscope  globe;  to  illustrate 
non-transmission  of  sound,  shaking  the  globe  before  and  after  exhaustion  shows  that  the  tinkling 


of  the  bell  is  not  heard,  or  heard  only  dimly,  when  the  globe  is  in  exhausted  state . $5.40 

43-310  FREEZING  APPARATUS,  illustrating  freezing  by  the  rapid  evaporation  of  ether  or  other  volatile 

liquids .  1.40 


No.  43-315  No.  43-326 


43-316  DEMONSTRATION  NITROGEN  FILLED  INCANDESCENT  LAMP.  A  heavy  glass  globe  fitted 
with  metal  cap  and  stop-cock,  the  end  of  which  is  threaded  to  fit  the  air  pump.  Binding  posts 
are  hermetically  sealed  and  are  connected  directly  to  the  filament  holders.  Arranged  so  that  it 
may  be  filled  with  nitrogen  to  demonstrate  nitrogen  filled  lamps.  Complete  with  one-half  dozen 
special  filaments . $3.50 

43-317  DEMONSTRATION  INCANDESCENT  LAMP  FILAMENTS  for  use  with  above  .  Per  Dozen  .17 

43-325  DEMONSTRATION  ARC  LAMP  for  illustrating  passage  of  electric  current  through  rarefied  gases. 

This  apparatus  consists  of  a  bell  glass  with  two  lateral  openings  with  brass  caps,  through  the  center 
of  which  pass  the  sliding  rod  carbon  holders  held  in  sliding  grips  by  packing  screws.  These  sliding 
rods  are  terminated  by  hard  rubber  handles  and  are  provided  with  binding  screws  for  attachment 
of  electric  current.  As  the  bell  glass  is  10  inches  in  diameter,  a  pump  plate  of  that  size  must  be 
used  with  this  instrument. 

This  apparatus  is  carefully  made  and  the  experiment,  if  properly  conducted,  is  exceedingly  instruc¬ 


tive  and  the  results  spectacular. 

Complete  with  extra  pair  of  carbon  pencils . Duty  Free  14.66 

43-326  CARBON  PENCILS  for  use  with  above . Per  Dozen  1.76 


160  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


BAROMETERS 


The  value  of  the  Weather  Bureau  Type  of  Barometer  has  been  realized  in  no  small  degree 
because  of  the  large  reservoir  in  which  the  height  of  the  mercury  is  adjusted  by  means  of  the  screw 
plunger  at  the  bottom,  the  correct  zero  being  indicated  by  a  pearl  white  pointer  projecting  down¬ 
ward  towards  the  surface  of  the  mercury.  This  indicator  being  fixed,  and  the  scale  rigidly  attached 
with  reference  to  it,  the  level  of  the  mercury  is  readily  brought  to  the  correct  zero  point  before 
each  reading.  Many  other  methods  of  adjustment  have  been  devised,  but  none  have  even  ap¬ 
proached  this  for  accuracy  and  ease  of  operation. 


/ 


45-10  FORTIN  SCHOOL  BAROMETER,  with  cistern  and  method  of 

adjustment,  same  as  described  above. 

SCALE  in  both  English  and  Metric  systems  with  clearly  indi¬ 
cated  divisions. 

TUBE  of  generous  proportions  filled  with  greatest  care. 
MOUNTING,  well  seasoned  hardwood  with  rosewood  finish, 
and  protecting  cap  over  the  reservoir  to  prevent  breakage, 
so  designed  as  to  permit  clear  view  of  both  pointer  and  mercury 
in  the  reservoir . $9.85 


45-15  FORTIN  CISTERN  SCHOOL  BAROMETER  WITH  VER¬ 
NIER,  double  scale,  double  vernier,  and  thermometer.  Scale 
reads  from  24  to  32  inches  with  equivalent  metric  scale, 
reading  with  vernier  to  %  millimeter  or  Vioo  inch . 16.80 


45-20  WEATHER  BUREAU  FORTIN  BAROMETER,  with  extra 
large  mercury  tube,  cylindrical  bulb  mounted  in  oxidized 
brass,  with  insulating  support  and  binding  screws,  thermome¬ 
ter  with  graduated  stem  scale,  a  thoroughly  high  grade  in¬ 
strument  of  a  type  used  in  all  Weather  Bureau  Stations  .  .  40.00 


46-25  MOUNTING  BOARD  of  mahogany,  rosewood  finish,  support¬ 
ing  arm  with  locknut,  dead  white  plate  back  of  scale  and 
mercury  cistern,  provided  with  screws  for  supporting  in  a 
vertical  position . 4.86 


No.  46-20 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


161 


No.  46-30 


No.  46-40 


46-30  DEMONSTRATION  ANEROID  BAROMETER,  desirable  for  the  explanation  and  illustration  of  the 
mechanism  of  the  ordinary  Aneroid  Barometer. 

This  instrument  is  ample  in  size  for  lecture  room  use  and  is  particularly  adapted  to  such  use  in  that 
all  parts  are  uncovered  and  can  be  distinctly  viewed  through  a  glass  dome.  Parts  mounted  on  a 
polished  hardwood  base.  Vacuum  chamber  connected  with  a  length  of  rubber  tubing  which  can  be 
connected  to  small  capacity  air  pump  or  demonstrated  more  simply  by  blowing  in  or  drawing  out 
the  air  through  the  mouth.  The  varying  pressure  is  readily  shown  by  means  of  the  indicating 
hand  over  the  scale. 

This  instrument  is  a  beautiful  ornament  and  its  construction  is  accurate  enough  for  barometric  ob¬ 
servations  .  . $18.26 


No.  46-60 


46-40  ANEROID  BAROMETER,  adjusted  for  altitudes 
up  to  3,500  feet,  improved  form,  4  inches  in 
diameter,  mechanism  mounted  in  highly  pol¬ 
ished  and  nickel-plated  brass  case.  Dial  open 
that  mechanism  may  be  in  full  view.  Grad¬ 
uations  read  in  both  the  English  and  the  Metric 
system .  4.26 

46-60  ANEROID  BAROMETER,  adjusted  for  altitudes 
up  to  3,500  feet,  brass  case  with  closed  silvered- 
metal  dial  5  inches  in  diameter. 

This  barometer  is  improved  by  a  patent  altitude  ad¬ 
justment  which  consists  of  an  auxiliary  hand. 

This  hand  is  adjustably  attached  to  the  pressure 
hand  and  moves  with  it.  While  the  pressure 
hand  shows  the  actual  atmospheric  pressure 
at  the  altitude  at  which  the  Aneroid  is  used,  the 
patent  adjustment  hand  may  be  so  regulated 
as  to  show  also  the  corresponding  sea-level 
pressure . . Each 

46-66  HIGH  ALTITUDE  ANEROID  BAROMETER. 

The  movements  of  this  barometer  are  of  good 
quality  and  in  their  general  construction  are 
identical  to  those  illustrated  in  No.  46—40;  ad¬ 
justed  for  use  between  4,900  and  9,500  feet. 
Mechanism  enclosed  in  polished  brass  case  and 
open  porcelain  dial  so  that  mechanism  is  in  full 
view . 

45-67  - ,  same  as  above,  but  of  special  design,  most 

careful  construction,  and  compensated  for 
changes  in  temperature.  Adjusted  for  use  be¬ 
tween  5,950  feet  and  11,800  feet.  Mechanism 
enclosed  in  polished  brass  case  with  open  sil¬ 
vered  metal  dial.  Mechanism  in  full  view  .  .  17.26 


8.00 


10.25 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


162 


45-65 


45-67 

45- 69 

46- 71 


# 


POCKET  MOUNTAIN  ANEROID  BAROMETER,  watch 
case  form.  This  is  a  highest  quality  Aneroid,  1%  inches 
in  diameter,  compensated  for  temperature,  silvered- 
metal  dial,  revolving  altitude  scale.  Enclosed  in  polished 
brass  case.  Adjusted  to  read  to  3,000  feet.  Enclosed  in 
neat  morocco,  plush-lined  case  .  ..  ....  .  ...  . 


- .  same  as  above,  but  adjusted  to  read  to  8,000  feet  .  . 

- ,  same  as  above,  but  adjusted  to  read  to  10,000  feet  . 

4 

- ,  same  as  above,  but  adjusted  to  read  to  16,000  feet  . 


$16.00 

17.26 

18.60 

19.75 


CHANG. 


COMPENSATED 


No.  45-67 


No.  45-100 


45-100  RECORDING  BAROMETER  (BAROGRAPH).  Barographs  are  instruments  arranged  to  record 
upon  a  chart  all  atmospheric  changes  in  pressure,  the  amount  of  rise  and  fall  of  same,  and  the  time 
such  changes  occurred.  The  mechanism  of  the  ordinary  barograph  consists  of  a  “pile”  or  series 
of  vacuum  chambers  each  secured  to  the  other  above  and  below  making  a  greatly  magnified 
sensitive  movement.  This  movement  is  further  magnified  and  transmitted  to  an  aluminum  re¬ 
cording  arm  carrying  a  pen  by  a  series  of  connecting  levers.  This  pen  records  the  changes  in  pres¬ 
sure  on  a  chart  which  encircles  a  drum  containing  a  clock  movement.  As  this  clock  revolves  once 
in  seven  days,  a  week’s  record  can  be  obtained  on  the  chart.  As  the  top  of  the  chart  is  divided 
into  seven  spaces,  each  allotted  for  one  day  a  week  and  sub-divided  into  spaces  representing  two 
hours,  it  is  possible  to  tell  at  what  time  of  any  day  the  atmospheric  pressure  underwent  a  change. 

This  week’s  record  will  be  in  the  form  of  a  tracing  along  the  chart.  By  referring  to  the  top  of  the 
chart  it  may  be  noted  at  what  day  and  hour  a  rise  or  fall  of  pressure  occurred. 

A  Barograph,  then,  is  the  most  reliable  form  of  a  barometer  and  has  the  further  feature  that  observa¬ 
tions  are  recorded,  whereas  in  weather  prognostications  a  single  observation  of  the  barometer  is 
of  little  or  no  value. 

The  instrument  listed  above  has  for  years  been  the  standard  for  meteorological  work,  and  its  quality 
in  all  particulars  is  unquestioned.  In  addition  to  a  careful  and  accurate  fitting  and  adjusting  of 
parts  this  instrument  is  handsome  in  appearance  and  will  be  found  exceedingly  valuable  in  any  lab¬ 
oratory.  Enclosed  in  mahogany  frame  glass  case  cover. 

Complete,  with  one  year’s  supply  of  charts . . . .  $36.75 

45-102  BAROGRAPH  CHARTS  as  used  in  above  instrument.  Box  containing  one  year’s  supply  ....  2  60 


1 63 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


METEOROLOGICAL  THERMOMETERS 


63-10  HOUSEHOLD  THERMOMETER,  8  inches  long,  heavy  metal  frame,  black  metal  scale  with  white 

figures,  reading  from  -30°  to  120°  F . $0.60 

63-12  HOUSEHOLD  THERMOMETER,  10  inches  long,  metal  scale  on  hardwood  back,  reading  from  -30° 

to  120°  F . 96 


46-30  WEATHER  BUREAU  PATTERN  THERMOMETER  WITH  CERTIFICATE,  engraved  stem,  magni¬ 
fying  mercury  tube,  cylindrical  bulb,  porcelain  strip  at  side  of  tube  in  which  are  marked  the  figures 
and  every  fifth  degree  line  of  the  scale,  oxidized  black  plate,  insulating  brass  support  with  binding 


screws.  Scale  range  40°  below  zero  to  120°  F.  above .  6.45 

46-36  SIX’S  MAXIMUM  AND  MINIMUM  SELF-REGISTERING  THERMOMETER,  black  oxidized 
brass  scales,  white  filled  figures,  japanned  tin  case,  length  8  inches,  scale  range  10°  to  40°  below 
zero  to  120°  F.  above.  Enclosed  in  box .  3.35 


THERMOMETRIC  CONVERSION  FACTORS 


F  =  9/5  C+32 
C  =  5/9  (F-32) 
R  =  4/9  (F-32) 


F  =  9/4  R+32 
C  =  5/4  R 
R  =  4/5  C 


164  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


46  40  MAXIMUM  AND  MINIMUM  THERMOMETERS,  medium  grade  thermometers  with  magnifying 

tubes  and  black  oxidized  brass  scales,  each  tube  10  inches  long,  mounted  on  a  separate  plate  attached 
at  one  end  with  a  thumb  screw  to  the  oak  back  so  that  the  thermometers  may  be  reset  as  illustrated 
above  . $3.90 


46-50  WEATHER  BUREAU  MAXIMUM  SELF-REGISTERING  THERMOMETER,  scale  range  40° 

below  zero  to  120°  F.  above. 

This  thermometer  has  an  engraved  stem,  magnifying  tube,  cylindrical  bulb,  porcelain  strip  at  side 
of  tube  on  which  are  marked  the  figures  and  every  fifth  degree  line  of  the  scale.  It  is  mounted  on 
an  oxidized  brass  plate  with  insulating  brass  support  with  binding  screws.  Each  thermometer  is 
12  inches  long  and  is  furnished  with  a  certificate  of  accuracy. 

Enclosed  in  box .  6.36 

46-61  WEATHER  BUREAU  MINIMUM  SELF-REGISTERING  THERMOMETER,  as  above  described, 

range  20  to  60°  below  zero  to  120°  F.  above.  Each  thermometer  is  12  inches  long  and  is  furnished 
with  a  certificate  of  accuracy. 

Enclosed  in  box  .  5-85 

46-62  WEATHER  BUREAU  MAXIMUM  AND  MINIMUM  SELF-REGISTERING  SET.  This  outfit 
consists  of  the  Maximum  and  Minimum  Thermometers  above,  appropriately  mounted  on  a  polished 

mahogany  board  17  inches  long  by  5  inches  wide.  Each  thermometer  is  furnished  with  a  certificate 

* 

of  accuracy. 

The  whole,  enclosed  in  a  neat  box . 12.00 


46-70  SOIL  THERMOMETER,  16-inch  wood  frame  with  handle,  brass  pointed  ferrule,  glass  cylinder, 
hand  written  paper  scale . 


1.40 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


165 


No.  46-110 


46-110  RECORDING  THERMOMETER  (THERMOGRAPH).  What  has  been  said  of  the  advantages 
of  the  use  of  a  barograph  may  just  as  consistently  be  repeated  regarding  the  advantages  of  the 
use  of  the  thermograph.  The  continuous  record  of  temperature  changes  is  necessary  in  any  inten¬ 
sive  study  of  Meteorology. 

Our  line  of  Thermographs  consists  of  bi-metallic  lamina  arranged  in  such  a  manner  that  there  are 
no  levers  other  than  the  pen  arm  used  in  its  construction.  This  construction  insures  rigidity, 
overcoming  all  lag  or  creep  and  friction,  and  in  consequence  is  much  more  sensitive  to  slight  changes 
in  temperature  than  the  standard  mercurial  thermometer. 

This  instrument  is  an  8-day  cylinder  clock,  low  drum  type,  chart  showing  range  from  30°  below  to 
110°  F.  above.  Movement  enclosed  in  a  hinged  metal  case  with  padlock.  This  case  is  supplied 
with  glass  window,  well  ventilated,  and  with  leather  handle  for  carrying. 

Complete  with  one  year’s  supply  of  charts . • . $36.76 

46-112  THERMOGRAPH  CHARTS,  as  usted  in  above  instrument.  Box  containing  one  year’s  supply  .  .  2.60 


No.  46-120 


46-120  BARO-THERMO  RECORDER  (COMBINED  THERMOGRAPH  AND  BAROGRAPH).  The 

above  illustration  pictures  a  recent  improvement  which  has  been  introduced  in  recording  instru¬ 
ments  by  combining  the  Barograph  and  the  Thermograph  in  the  same  instrument.  The  records 
are  given  on  the  same  chart,  but  in  different  colored  inks  to  prevent  confusion  (blue  for  the  Baro¬ 


graph  and  green  for  the  Thermograph). 

Baro-Thermo  Recorder . $60.00 

46-122  BARO-THERMO  RECORDER  CHARTS,  one  year’s  supply,  for  use  with  above .  2.76 


i66 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


HUMIDITY  INDICATORS  AND  RECORDERS 


No.  47-20 


47-10  “SLING”  PSYCHROMETER  OR  HYGROMETER  for  obtaining  quick  and  more  accurate  results 
than  are  possible  with  the  stationary  wet  and  dry  bulb  instruments. 

This  instrument  consists  of  two  accurate  thermoftieters  firmly  attached  to  a  metal  arm  swiveled  to  a 
wood  handle.  In  use  one  of  these  bulbs  is  covered  with  a  wicking  which  should  be  thoroughly  sat¬ 
urated  with  water.  To  obtain  readings,  whirl  the  instrument  fifteen  or  twenty  seconds,  holding  it 
well  away  from  the  body.  Stop  and  note  the  wet  bulb  temperature;  continue  the  operation,  whirling 
and  reading  until  two  readings  of  the  wet  bulb  thermometer  are  obtained  alike  or  nearly  so.  This 
will  be  the  lowest  temperature.  Tables  and  full  directions  are  supplied  with  the  instrument  to 
determine  the  per  cent,  of  relative  humidity . Each  $2.50 

47-15  MASON’S  HYGROMETER  (Wet  and  Dry  Bulb),  good  quality,  magnifying  mercury  tube,  silvered 
brass  scales  with  black  filled  figures  and  graduations,  mounted  on  polished  oak  board  11X5  inches. 
Enclosed  in  a  box .  3.36 

47-20  WEATHER  BUREAU  PATTERN  HYGROMETER  (Wet  and  Dry 
Bulb),  consisting  of  two  No.  46-30  Standard  Thermometers 
mounted  on  a  polished  mahogany  board  17  X  5  inches  with 
nickel-plated  brass  cistern  and  silk  wick. 

This  instrument  is  the  United  States  Standard  and  may  be  depended 
upon  for  the  utmost  accuracy. 

Each  thermometer  is  supplied  with  a  certificate  of  correction.  En¬ 
closed  in  box  .  . $11.80 

47-25  SPIRAL  HYGROMETER,  80  millimeters  diameter. 

This  simple  little  instrument,  with  handsomely  nickeled  case,  is  pro¬ 
vided  with  a  scale  denoting  the  humidity  of  the  air  without  refer¬ 
ence  to  tables 


No.  47-26 


2.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


167 


No.  47-40 


No.  47-76 


47-40  DIRECT  READING  HUMIDITY  APPARATUS  (HYGROPHANT),  a  simple,  convenient,  and  efficient 
means  of  determining  both  the  temperature  and  humidity  of  the  air  with  accuracy  and  without 
computation. 

This  instrument  is  provided  with  two  standard  thermometers,  one  showing  the  temperature  of  the  air, 
the  other  the  temperature  due  to  evaporation.  A  cylinder  upon  which  is  inscribed  a  series  of  col¬ 
umns  of  figures  numbered  at  their  headings  from  1  to  22  may  be  noted  between  the  thermometers. 
These  strips  represent  the  difference  in  degrees  between  the  indications  of  the  thermometers  and  the 
columns  exhibiting  relative  humidity  or  percentage  of  moisture  in  the  air  for  every  degree  of  tem¬ 
perature  indicated  by  the  thermometer.  A  fixed  scale  upon  the  casing  in  which  the  cylinder  revolves 
indicates  the  relative  humidity  or  percentage  of  moisture  in  the  air. 

In  use  the  cup  is  filled  with  pure  water  into  which  dips  the  wicking  attached  to  the  wet  bulb  ther¬ 
mometer.  As  soon  as  this  wicking  and  gauze  which  covers  bulb  become  wet  the  instrument  is  ready 
for  use.  In  ascertaining  the  actual  temperature,  read  the  indication  of  the  thermometer  on  the 
right  of  the  instrument;  in  ascertaining  the  temperature  due  to  evaporation  read  the  indications 
of  the  wet  bulb  thermometer.  Now  note  the  difference  in  number  of  degrees  between  the  two 
thermometers.  Turn  the  cylinder  by  means  of  the  knob  on  the  top  so  as  to  present  to  view  the 
column  of  figures  having  at  its  head  the  number  corresponding  to  this  difference.  In  line  then  with 
the  division  on  the  fixed  scale  which  corresponds  to  the  degree  indicated  by  the  wet  bulb  thermome¬ 
ter,  may  be  read  the  relative  humidity  or  percentage  of  moisture  in  the  air. 

Complete  with  full  and  explicit  directions  for  use . ■ .  .  .  . 


47-66  RAIN  GAUGE,  United  States  Weather  Bureau  type,  diameter  3  inches,  height  13  inches,  with  over¬ 
flow  and  measuring  stick . 


47-76  REGISTERING  RAIN  GAUGE.  The  rain  gauge  illustrated  above  is  a  pattern  which  is  known  as 
the  “tilting  bucket”  gauge.  No  measurement  is  necessary  as  the  rain  is  collected  in  the  8-inch 
receiver  and  is  taken  through  a  small  pipe  and  dropped  into  one  side  of  a  bucket.  When  a  given 
amount  of  rain  has  collected  in  the  bucket  (0.01  inch)  the  weight  of  the  rain  on  the  laden  side  causes 
it  to  overbalance,  and  by  a  mechanical  arrangement  the  hand  moves  0.01  inch  at  each  opera¬ 
tion. 

The  rain  still  passing  through  the  receiver  is  collected  in  the  opposite  bucket.  When  that  has  received 
the  given  amount  the  same  operation  is  repeated.  The  great  advantage  of  this  type  of  gauge  is 
that  it  is  zero  set  and  is  particularly  useful  when  a  person  wants  to  keep  a  record  of  rainfall  by 
the  month  or  week.  The  dial  registers  one  inch  by  0.01  inch;  the  second  or  smaller  dial  reads  up¬ 
wards  of  12  inches. 

Enclosed  in  metal  case  10  X  8  inches 


$9.60 


2.76 


24.76 


1 68 


L .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  48-12  No.  48-30  No.  48-17 

48-10  ANEMOMETER  for  measuring  air  currents  through  tunnels,  mines,  ventilators  of  public  buildings, 
etc.  The  indications  are  obtained  by  means  of  a  delicately  poised  fan  wheel,  the  recordings  be¬ 
ing  started  by  the  long  hand  which  traverses  the  outer  circumference  of  the  main  dial  which  indi¬ 
cates  a  passage  of  100  feet  of  air.  This  recording  is  continued  up  to  10,000,000  feet  by  a  series  of 
smaller  dials,  six  in  number.  The  disconnector  projecting  from  the  band  of  the  instrument  opposite 
the  fan  wheel  serves  to  throw  the  mechanism  out  of  gear,  arresting  its  action  when  required. 

In  use  the  instrument  is  placed  in  the  current  in  a  number  of  different  positions.  Take  the  number  of 
feet  that  have  passed  during  a  certain  time,  for  example  one  minute,  divide  the  total  by  the  number 
of  readings  and  obtain  the  average.  Multiply  this  average  by  the  square  of  the  opening  and  the 
result  is  the  velocity  of  air  in  feet  passing  in  a  given  time. 

Each  instrument  is  enclosed  with  zero  setting  attachment  in  a  neat  mahogany  case . .  $24.75 

48-12  -  — ,  same  as  above,  but  with  four  dials  reading  to  100,000  feet.  This  instrument  is  recommended  in 

preference  to  above  in  that  the  parts  are  not  so  delicate . 24.76 

48-16  BIRAM’S  ANEMOMETER  for  similar  use  as  No.  48-10.  In  this  type  of  instrument  the  revolutions 
are  recorded  on  a  dial  in  the  center  of  the  instrument.  Each  instrument  is  tested  and  furnished 
with  a  chart  of  corrections,  supplied  with  patent  zero  setting  attachment  in  neat  mahogany  box, 
diameter  3  inches,  two  dials  reading  to  1,000  feet.  This  instrument  will  stand  a  pressure  of  1,000 
feet  per  minute . 22.60 

48-17  - ,  similar  to  above,  4  inches  in  diameter  with  four  dials  reading  to  100,000  feet;  will  stand  pressure 

of  3,000  feet  per  minute . 23.80 

48-30  REGISTERING  ANEMOMETER.  This  simple  device  for  indicating  the  velocity  of  the  wind  in 
miles  consists  of  a  vertical  shaft,  to  the  upper  end  of  which  are  fastened  four  arms,  each  carrying  a 
Robinson  hemispherical  copper  cup.  These  cups  turn  in  one  direction,  regardless  of  the  direction 
of  the  wind,  and  at  a  ratio  determined  by  experiment.  To  the  lower  end  of  the  shaft  is  fastened 
an  endless  screw  which,  as  the  shaft  revolves,  actuates  a  wheel  which  in  turn  meshes  into  a  series  of 
other  wheels;  thus  the  miles  are  indicated  on  the  registering  dial.  The  dial  is  so  arranged  as  to  show 
velocities  from  one-tenth  of  a  mile  to  10,000  miles,  and  then  it  repeats,  commencing  at  zero. 

To  ascertain  the  rate  in  miles  per  hour  at  which  the  wind  is  traveling,  make  two  readings  with  an  in¬ 
terval  of  ten  minutes  and  multiply  the  difference  by  six. 

This  instrument  is  carefully  made  and  requires  but  little  attention.  All  parts  are  interchangeable  .  30.00 


48-100 

I' 

■  • 


48-102 


HARCOURT  STUDENTS’  METEOROLOGICAL  EQUIPMENT.  This  is  a  complete  set  of  Mete¬ 
orological  instruments  of  standard  quality  suitable  for  all  work.  The  set  must  not  be  confused 
with  various  types  on  the  market  inasmuch  as  our  set  comprises  standard  instruments  of  medium 
quality.  The  set  consists  of  the  following,  —  one  10-inch  Thermometer,  metal  scale  on  hard¬ 
wood  back;  one  10-inch  Maximum  and  Minimum  Thermometer,  mounted  on  hardwood  back; 
one  Mason’s  Hygrometer,  mounted  on  polished  oak  board  11X5  inches;  one  4-inch  Aneroid 
Barometer,  open  dial,  graduations  both  English  and  Metric  systems,  and  one  3-inch  U.  S.  Weather 
Bureau  Rain  Gauge  with  Measuring  Stick. 

The  various  instruments  cited  above,  with  the  exception  of  the  Rain  Gauge,  may  be  mounted  within 
the  Instrument  Shelter  as  illustrated.  This  Instrument  Shelter  is  of  substantial  structure,  painted 
inside  and  out  with  a  durable  coat  of  lead  paint.  It  is  provided  with  brackets  for  attachment 
to  wall. 

Instrument  Shelter  complete  as  illustrated,  with  all  instruments,  including  Rain  Gauge . 


■,  as  above  illustrated,  but  without  Rain  Gauge 


INSTRUMENT  SHELTERS 


48-106  INSTRUMENT  SHELTER,  as  above  described  in  No.  48-100  but  without  instruments . 

48-116  INSTRUMENT  SHELTER.  Meteorology  and  climatology  study  in  our  schools  has  so  come  to 
the  front  during  the  last  few  years  that  it  has  become  almost  essential  that  a  shelter  for  recording 
instruments  be  provided  for  outside  use. 

Our  instrument  is  constructed  after  the  latest  pattern  Weather  Bureau  Instrument  Shelter  and  may 
be  mounted  on  legs  for  use  on  the  school  grounds  or  attached  to  the  side  of  a  wall.  It  is  sufficiently 
large  to  hold  easily  both  a  Barograph  and  Thermograph,  a  Hygrometer  and  a  set  of  Maximum 
and  Minimum  Thermometers,  an  Aneroid  Barometer  and  a  Thermometer.  It  is  constructed  of 
the  best  quality  straight-grained  pine  with  swing  door  provided  with  lock  and  key.  We  secure 
perfect  circulation  of  air  and  obstruction  to  rain  by  means  of  the  blind  construction  usually  em¬ 
ployed  in  the  manufacture  of  shelters.  It  is  painted  outside  and  in  with  a  durable  coat  of  lead 
paint. 

Instrument  Shelter,  complete  ready  for  mounting,  but  without  instruments  of  any  kind . 


169 


$16.26 

12.60 

$6.80 


20.00 


170 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


NO.  49-90 

HACKELING  TELLURIAN 

Patent  No.  868,977,  Issued  July  2,  1907 


A  simplified  and  improved  form  of  Tellurian,  invented  by  the  late  Dr.  Hermann  A.  Hackeling.  This  instru¬ 
ment  was  designed  with  special  reference  to  the  needs  of  the  instructor  teaching  Geography  in  the  last  year  of  the 
grammar  school  and  the  first  year  in  high  school,  bearing  in  mind,  also,  its  special  usefulness  in  teaching  Physical 
Geography  and  General  Science  in  the  first  and  second  year  of  high  school  work. 

To  quote  Dr.  Hackeling’s  own  words,  his  purpose  was  to  “design  an  educational  Tellurian  which  could  be  supplied 
to  schools  at  a  comparatively  low  price  and  which  would  make  clear  to  the  student  the  relative  positions  of  the  sun, 
earth,  and  moon,  and  the  inter-relations  resulting  from  their  rotation  and  revolution.” 

Our  designing  department  has  given  careful  study  to  Dr.  Hackeling’s  excellent  design  and  has  been  able  to  im¬ 
prove  upon  it  only  to  the  extent  of  adapting  the  design  to  factory  methods  of  production,  thus  insuring  greater  strength 
of  working  parts  and,  at  the  same  time,  making  it  possible  to  offer  the  instrument  at  a  lower  price. 

As  will  be  noted  from  the  cut,  all  unnecessary  features  have  been  omitted  and  the  essential  parts  have  been  sim¬ 
plified  and  strengthened.  All  mechanical  parts  are  exposed  to  view,  these  parts  being  so  simplified  and  strengthened 
as  to  insure  the  instrument  not  getting  out  of  order. 

Please  note  that  in  rotating  the  earth  around  the  sun,  the  earth  is  at  the  same  time  given  a  positive  and  exact 
revolution,  carrying  with  it  the  moon,  the  position  of  the  moon  with  reference  to  the  earth  and  the  sun  being  varied 
by  sliding  vertically  on  the  supporting  rod. 

Also  note  that  the  entire  system,  by  loosening  of  the  T-Screw,  may  be  moved  to  a  horizontal  position,  without 
changing  the  relation  previously  existing  between  the  three  bodies. 

All  metal  parts  are  of  substantial  construction,  well  finished;  the  base  being  made  of  5-ply,  well  seasoned  hard 
wood,  neatly  finished. 

This  instrument  has  been  pronounced  by  those  who  have  given  much  study  to  this  important,  feature  of  educa¬ 
tional  work,  the  only  one  which  produces  the  desired  results  in  a  simple  and  direct  way  and  so  designed  mechanically 
as  to  insure  its  not  getting  out  of  order. 


$15.00 

Special  price  will  be  quoted  upon  these  in  dozen  lots,  where  it  is  desired  to  place  the  instrument  directly  in  the 
hands  of  the  student.  . 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


171 


THE  NEWELL  COLLECTION 

OF 

LANTERN  SLIDES  IN  CHEMISTRY 


Selected  and  arranged  by  Lyman  C.  Newell,  Ph.D.,  Professor  of  Chemistry,  Boston  University,  Boston,  Mass 


The  slides  in  this  collection  will  be  found  of  particular  advantage  in  courses  dealing  with  the  historical  side  of 
Chemistry.  There  are  104  slides  in  the  series,  each  slide,  each  subject  most  carefully  selected.  The  series  is  par¬ 
ticularly  valuable  in  that  it  contains  so  many  slides  of  eminent  chemists,  —  American,  Dutch,  English,  French,  Ger¬ 
man  and  Italian,  all  of  which  are  remarkably  clear  and  distinct.  The  following  subjects  are  stressed,  —  Alchemy, 
Atmosphere,  Atomic  Theory,  Atomic  Weights,  Avogadro’s  Hypothesis,  Combustion,  Electro  Chemistry,  Elements, 
Metals,  Halogens,  and  Chemistry  in  Eighteenth  and  Nineteenth  Centuries. 


Single  Slides . Each  $0.40 

Any  60  in  Regular  Lantern  Slide  Box .  . 20.00 


A  descriptive  circular  free  upon  request. 


FIVE  HUNDRED  AND  FIFTY 

LANTERN  SLIDES  AND  STEREOGRAPHS 

Selected  and  described  with  Special  Reference  to 
STUDY  OF  PHYSICAL  GEOGRAPHY  AND  GEOLOGY 

BY 

WALLACE  W.  ATWOOD,  PH.D.,  JANE  PERRY  COOK, 

Instructor  in  Physiography  and  Head  of  Department  of  Geography, 

General  Geology,  University  of  Chicago.  Chicago  Normal  School. 


This  series  of  slides  has  been  selected  and  classified  according  to  those  topics  in  Physical  Geography  and  Geol¬ 
ogy  to  be  found  in  the  best  courses  of  study  and  in  the  modern  text-books  on  these  subjects.  The  classification  has 
been  systematic  and  thorough. 

The  catalogue  of  these  slides,  which  may  be  obtained  free  upon  request,  is  divided  for  ready  reference  into  main 
topics,  —  Weathering,  Sand  Dunes,  Rivers  and  River  Valleys,  Underground  Water,  Glaciers,  Lakes,  Shore  Lines 
and  Harbors,  Vulcanism,  Earthquakes,  Mountains,  Plains,  Clouds,  Storms  and  Life  Forms  in  Various  Physiographic 
Environments.  Each  main  topic  is  logically  divided  into  subdivisions,  e.  g.,  49  pictures  have  been  selected  for  the 
study  of  Glaciers  under  the  following  subtopics:  —  The  Study  of  a  Glacier,  European  Glaciers,  Study  of  Glaciated 
Valleys  and  Ascent  of  Mt.  Hood.  Each  slide  has  been  most  carefully  selected  as  best  adapted  to  each  particular 
subtopic. 

The  value  of  this  series  is  further  enhanced  by  brief  descriptive  matter  printed  on  the  back  of  each  stereograph 
and  in  the  case  of  slides  on  slips  of  heavy  book  paper.  These  printed  slips  are  put  up  in  a  neat  and  attractive  book¬ 
let  which  is  sent  along  with  the  order.  When  all  the  slides  of  a  single  topic  are  ordered  the  booklet  makes  a  most 
valuable  body  of  supplementary  reading  matter  on  the  subject. 

Single  Slides . Each  $0.40 

Per  One  Hundred . 36.00 


Send  for  Special  Catalogue  descriptive  of  these  slides. 


172 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  i 


49-100  KULLMER  STAR  CHART.  This  new 
astronomical  instrument  is  based  on  the 
principle  of  the  equatorial  telescope  mount¬ 
ing,  —  an  arrow  taking  the  place  of  the 
telescope.  It  is  so  simple  and  ingenious 
that  it  is  fascinating  to  operate.  In  the 
cut  the  instrument  is  set  for  February  22, 
at  9  P.M.  Place  the  arrow  wherever  you 
wish,  and  it  will  be  pointing,  when  proper¬ 
ly  set,  at  the  star-group  shown  and  named 
in  the  opening  of  the  indicator  below. 


No.  49-100 


SOME  OF  THE  THINGS  IT  TEACHES. 

The  apparent  daily  rotation  of  the  whole  sky. 

Where  stars,  sun,  moon  and  planets  rise  and  set  and 
the  actual  path  taken  by  them. 

The  seasons,  movement  of  sun  north  and  south  and 
path  at  solstices  and  equinoxes. 

The  constellations, — locations  and  names. 

Sidereal  and  solar  time. 

Right  Ascension  and  Declination. 

Etc.,  etc.,  etc. 

Made  of  nickeled  metal  with  celluloid  dial 
that  can  be  washed  when  desired.  With 
booklet  “Star  Maps  and  Star  Facts”  in 
neat  leatherette  case  . 


$5.00 


49-110  SEASONAL  TWILIGHT  CHART,  designed  and  copy¬ 
righted  1907  by  Miss  E.  Rebecca  Ellis  of  the  Depart¬ 
ment  of  Physical  Astronomy  at  Wellesley  College, 
for  showing: 

The  comparative  lengths  of  day,  night  and  twilight  at  any  place 
at  different  seasons  of  the  year. 

The  comparative  lengths  of  day,  night  and  twilight  at  different 
places  at  the  same  season  of  the  year. 

The  absolute  lengths  of  day,  night  and  twilight  at  any  place  at 
any  season. 

The  time  of  sunrise  and  sunset  at  any  place  at  any  season. 

The  azimuth  of  sunrise  and  sunset  points  at  any  place  at  any 
season. 

The  noon  elevation  of  the  sun  at  any  place  at  any  season. 

The  midnight  depression  of  the  sun  at  any  place  at  any  season. 

The  phenomena  of  the  midnight  sun. 

The  diurnal  path  of  the  sun  at  the  poles  (six  months  day  and  six 
months  night) . 

The  diurnal  path  of  the  sun  at  the  equator  (days  and  nights 
equal:  and  extremely  short  twilight). 


No.  49-110 


This  chart  is  the  orthographic  projection  of  a  globe  upon  a  plane  from  a  due  east  point  in  the  plane 
of  the  horizon.  The  chart  is  12  X  12  inches,  divisions  and  figures  distinct  and  legible  and  the  size 
ample  for  use  to  advantage  on  the  lecture  table.  The  student,  however,  will  gain  a  much  clearer 
grasp  of  the  whole  subject  if  he  works  out  the  various  problems  with  the  chart  in  hand. 


With  full  directions 


Each  Chart  $1.00.  Per  Dozen  $9-W 


CATALOGUE  OF  PHYSICAL,  INSTRUMENTS 


173 


No.  49-120 

THE  B-K  SOLAR  CALCULATOR 

Invented  by  FRANK  L.  BRYANT 

ERASMUS  HALL  HIGH  SCHOOL,  BROOKLYN,  N.  Y. 


No.  49-120 


The  object  of  this  ingenious  instrument  is  to  provide  a  simple  apparatus  for  teaching  the  fundamental  ideas  of 
i  apparent  motion  of  the  sun  in  relation  to  any  point  on  the  earth’s  surface  and  at  any  time  of  the  year.  It  is 
jecially  designed  for  the  use  of  students  in  the  laboratory  for  working  out  certain  problems  which  will  be  noted 
low.  It  is  also  of  value  to  the  teacher  in  lecture  work  for  all  grades  of  geography  instruction  from  the  grammar 
100I  to  advanced  work  in  the  college. 

This  instrument,  about  16  inches  high  and  16  inches  wide,  is  especially  adapted  for  the  lecture  table,  although  it 
IS  primarily  designed  for  individual  student  use.  A  special  feature  in  connection  with  the  use  of  the  instrument, 
d  one  entirely  new,  is  that  the  horizon  disc  may  be  lowered  and  adjusted  for  plotting  shadow  curves  at  the  time 
the  solstices  and  equinoxes  for  different  latitudes.  This  work  was  practically  impossible  before  the  intro- 
ction  of  the  B-K  Solar  Calculator.  Its  value,  therefore,  will  be  especially  appreciated  by  teachers  of  Physical 
:ography. 

The  following  exercises  may  be  performed  by  the  use  of  the  instrument: 

1.  Find  the  time  of  sunrise  and  sunset  at  any  latitude  at  any  time  of  the  year. 

2.  Determine  the  length  of  day  at  any  latitude  at  any  time  of  the  year. 

3.  Find  the  relative  distribution  of  insolation  over  the  earth  at  different  times  of  year. 

4.  Find  the  direction  of  sunrise  and  sunset  at  any  latitude  at  any  time  of  the  year. 

5.  Find  the  altitude  of  the  sun  at  any  latitude  at  any  time  of  the  day  or  year. 

5.  Plot  the  curves  of  a  shadow  cast  by  an  upright  post  at  any  latitude  at  the  time  of  the  solstices  and  equinoxes. 

7.  Interpretations  of  shadow  curves. 

8.  Show  relation  of  elevation  of  celestial  pole  to  latitude. 

9.  Show  relation  of  zenith  distance  of  sun  to  latitude  at  different  times  of  the  year. 

10.  Show  relation  of  length  of  twilight  to  latitude  at  different  times  of  the  year. 

B-K  SOLAR  CALCULATOR,  brass  with  oak  base 
irections  for  use  furnished  with  each  instrument. 


Special  price  in  lots  of  ten. 


174 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


THE 


Set  for  Tropic  of  Capricorn 
23 S.  Lat. 


No.  49-120 

B-K  SOLAR  CALCULATOR 


Set  for  Tropic  of  Cancer, 
23  N.  Lat. 


Set  for  the  North  Pole,  90° 


Set  for  the  Arctic  Circle 
66^°  N.  Lat. 


Set  for  plotting  the  Shadow 
Curves  at  the  Equator 


FORMS  OF  SHADOW  CURVES 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


175 


No.  49-175 

CURTIS  NATURALISTIC  MODELS 

These  models  are  true  scale  reliefs,  9X9  inches,  representing  the  forms  of  the  earth’s  sur- 
|ice,  durably  constructed  of  a  special  composition,  beautifully  colored  to  reproduce  the  color  scheme 
f  the  natural  object.  They  may  be  handled  as  readily  as  a  school  book  and  used  wherever  Geog- 
aphy  is  taught.  They  are  especially  adapted  for  work  in  connection  with  courses  in  Physical 
ieography.  This  wide  range  of  service  is  due  to  the  fact  that  each  model  is  based  on  well  selected 
ypes  taken  from  actual  occurrences  in  the  field,  and  reproduced  in  very  characteristic  forms. 

While  it  is  true  that  the  beginners  will  get  but  a  small  portion  of  what  the  advanced  student 
nay  obtain,  they  will  lose  nothing  by  the  completeness  of  the  subject  and  what  they  do  gain  will 
jome  in  the  easiest  way. 

The  set  comprises  six  models,  each  enclosed  in  a  book-cover  case  into  which  the  models  slide, 
>ermitting  them  to  be  handled  and  stored  like  books.  The  set  consists  of  the  following: 

SEACOAST 


No.  I. 


SEASHORE  BORDERING  A  PLAIN 


176 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  49-175 


CURTIS  GEOGRAPHY  MODELS 

GLACIERS 


No.  I.  HEAD  OF  A  GLACIER 


No.  II.  LOWER  END  OF  A  GLACIER 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


177 


No.  49-175 

CURTIS  GEOGRAPHY  MODELS 

VOLCANOES 


No.  I.  A  FRAGMENTAL  CONE 

(VESUVIAN  TYPE) 


No.  II.  AN  OPEN  CRATER  (CALDERA) 


178 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  49-175 

CURTIS  GEOGRAPHY  MODELS 


1 


c"  *'* .  -j 

OC.OCHAPHV 

'AOOCl.!. 

SEACGAST 

No  I 

COASTAL 
PLAIN  : 


.  v'  $*'  s  .  •  .  r ,  V 

1  •  (,/u 

i'  '  OtOCRAPIIV  OfOOf\Ar»»Y 

NooeCft  noorLs 

SEACOAST  VOLCANOES 

No  n  M0  j 

MOUNTAIN 


<j«OORA»»HY 

MOMl* 


VOLCANOES  CLACK 


lUUN  I  HU  Y  nnnfJ^nrrta.  A  PRATFR  HEAD  OF 

COAST  CINDER  CONE  ALnAlLlI  A  GLACIER 


GLACIERS 

Noll 

FOOT  or 
A  GLACIER 


SET  OF  GEOGRAPHY  MODELS  IN  COVERS 


SEACOASTS 

No.  I.  SEACOAST  BORDERING  A  PLAIN. 

A  Plain  which  borders  the  sea. 

Rivers  which  cut  the  plain  and  empty  into  the  sea  through  an  estuary. 

A  Harbor  lying  at  the  head  of  the  bay  at  the  mouth  of  the  largest  stream  and  on  its  shores. 

A  Seaport  Town  situated  on  the  bay.  Vessels  may  lie  at  the  wharves,  load  and  discharge 
cargoes  well  sheltered  from  storms. 

No.  H.  EMBAYED  MOUNTAIN  COAST. 

A  Bay  reaching  up  into  the  mountainous  land. 

Mountain  Peaks  which  rise  abruptly  from  the  sea. 

A  Narrow  Valley  flanked  by  steep  mountain  sides. 

A  River  flowing  through  the  valley. 

A  Delta  at  mouth  of  the  river  and  head  of  the  bay. 


VOLCANOES 

No.  I.  FRAGMENTAL  CONE  (VESUVTAN  TYPE.) 

A  Young  Volcanic  Mountain  rising  from  the  sea. 

An  Active  Volcano  at  top  of  mountain;  hot  stones,  ashes,  lavas  running  down  the  sides  of  the 
mountain. 

Lava  “Flows”  showing  as  hardened  rock. 

An  Old  Volcanic  Mountain. 

No.  II.  AN  OPEN  CRATER  (CALDERA). 

The  Top  of  a  Volcano,  showing  devastated  region  about  the  summit. 

A  Deep  Crater  Pit,  a  “Caldera.” 

An  Old  Crater  partially  filled  with  lava. 

Fresh  Lava. 

GLACIERS 

No.  I.  HEAD  OF  A  GLACIER. 

Mountain  Peaks,  sharp  topped  ridges. 

Lofty  Valleys,  partially  filled  with  snow  and  ice,  descending  steeply. 

Snow  Fields,  masses  of  loose  and  compact  snow  which  feed  the  Rivers  of  Ice. 

Glaciers. 

No.  II.  LOWER  END  OF  A  GLACIER. 

The  Foot  of  a  Glacier. 

The  Head  of  a  River,  the  melting  glacier  giving  rise  to  a  river. 

An  Open  Valley. 

An  Alpine  Village,  low  huts  clustering  near  the  foot  of  the  glacier. 

Complete  set  of  six  models,  each  in  Book  Cover  Case,  appropriately  labeled,  including  a 

descriptive  manual,  a  complete  text  on  the  subjects  covered . $50.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


179 


SOUND 

PROPAGATION  OF  SOUND 

TUNING  FORKS 

• 

In  the  selection  of  our  TUNING  FORKS  we  have  been  guided  by  the  demands  of  the  past  which  we  have  classi¬ 
fied.  .  We  have,  therefore,  eliminated  certain  types  and  added  forms  of  greater  pedagogic  value.  Our  policy  is  to 
furnish  the  best  at  the  most  reasonable  prices,  offering  a  line  which  will  give  the  prospective  buyer  a  range  for  choice. 

For  ordinary  work,  we  recommend  our  Nos.  61-50  to  61-87.  These  forks  are  accurately  tested  and  have,  withi  n 
a  very  small  percentage  of  error,  the  stated  vibration  frequencies.  For  the  highest  scientific  work,  we  recommend 
Nos.  61-90  to  51-126. 

All  forks  are  tuned  to  the  Physical  Pitch,  and,  when  a  fork  is  mounted  on  Resonant  Case,  it  must  be  under¬ 
stood  that  the  case  is  accurately  tuned  in  resonance  with  the  fork. 


No.  61-60 

61-60  UNIVERSAL  PATENT  ADJUSTABLE  TUNING  FORK,  U.  S.  Standard  Pitch,  nickel-plated  .  .  $1.10 


No.  51-56 


51-55  TUNING  FORK,  12  centimeters  long,  best  polished  steel,  Pitch  A . $0.13 

51-57  - ,  12  centimeters  long,  best  polished  steel,  Pitch  C .  .13 


Nos.  61-75  to  51-87 


61-65  TUNING  FORK,  Pitch  C  =  128  VPS.  about  25  centimeters  long  .  $3.10 

61-75  - ,  Pitch  C1  =  256  VPS.  about  22  centimeters  long .  1.20 

61-76  - ,  Pitch  D  =  288  VPS.  about  21  centimeters  long .  1.46 

61-77  - ,  Pitch  E  =  320  VPS.  about  20  centimeters  long .  1.45 

61-78  - ,  Pitch  F  =  341  1/3  VPS.  about  20  centimeters  long .  1.45 

51-79  - ,  Pitch  G  -  384  VPS.  about  19  centimeters  long .  1.45 

61-80  - ,  Pitch  A  =  426  2/3  VPS.  about  19  centimeters  long .  1.26 

51-81  - ,  Pitch  B  =  480  VPS.  about  18  centimeters  long .  1.26 

61-82  - ,  Pitch  C2  =  512  VPS.  about  18  centimeters  long .  1.10 

51-85  TUNING  FORKS,  set  of  four,  giving  the  Major  Chord,  C1,  E,  G,  and  C2  .  6.10 

61-86  MOUNTED  TUNING  FORKS,  set  of  four,  C1,  E,  G,  C2,  as  listed  above,  mounted  on  resonant  cases  12.95 

61-87  TUNING  FORKS,  set  of  eight,  C1  to  C2,  giving  full  Octave.  Same  forks  as  Nos.  61-76  to  51-82  9.86 

61-88  RUBBER  HAMMER,  small . 14 

61-89  LARGE  LECTURE  TABLE  PURE  GUM  RUBBER  HAMMER,  finely  finished  handle . 66 


i8o 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


61-90  NORMAL  TUNING  FORKS  of  excellent  quality,  finely  nickel-plated,  accurately  adjusted.  Set 
of  eight  forks,  from  C  =  64  VPS.  to  C  =  128  VPS.,  the  largest  fork  about  40  centimeters  long,  the 
smallest  about  36}4  centimeters . . .  Duty  Free 


61-96  -  — ,  same  quality  as  above,  set  of  fifteen  forks,  from  C  =  64  VPS.  to  C1  =  256  VPS.  The  largest 
fork  about  44  centimeters  long,  the  smallest  about  23  centimeters  . Duty  Free 

61-100  - ,  same  quality  as  above,  set  of  eight  forks,  from  C  =  128  VPS.  to  C1  =256  VPS.  The  largest 

fork  about  36p£  centimeters  long,  the  smallest  about  23  centimeters  . Duty  Free 

61-106  EXTRA  HEAVY  TUNING  FORK,  C  =  64  VPS.,  44  centimeters  long . Duty  Free 

61-106  - ,  C  =  128  VPS.,  35  centimeters  long . Duty  Free 

61-116  STANDARD  NORMAL  TUNING  FORKS,  highest  quality  and  precision,  especially  designed  for 

research  in  acoustical  phenomena.  Set  of  six  large  nickel-plated  Forks,  C  =  128  VPS.,  C1  =  256 

VPS.,  C2  =  512  VPS.,  C*  =  1024  VPS.,  C4  =  2048  VPS.,  and  G4  =  3072  VPS.  Each  with  a  vi¬ 
bration  period  of  30  seconds.  Enclosed  in  handsome  plush-lined  case . Duty  Free 

61-120  STANDARD  NORMAL  TUNING  FORK,  finest,  quality,  highest  precision,  worked  out  of  a  heavy 
piece  of  steel,  not  cast,  with  certificate  of  accuracy  from  the  Physikalische  Techniche  Reich- 
sanstalt.  Enclosed  in  neat  case . Duty  Free 


61-126  FIFTY-CENTIMETER  TUNING  FORK  AFTER  BEZOLD,  for  demonstrating  the  minimum  limit 
of  the  normal  ear  for  sound. 

This  is  a  polished  steel  fork,  500  millimeters  long,  with  a  prong  350  millimeters  long,  each  prong  21  X  9 
millimeters.  Each  fork  has  received  the  most  painstaking  care  in  construction  and  is  carefully 
adjusted.  Adjustable  ballast  weights  are  provided  giving  vibration  frequencies  from  15  to  24. 
Handsomely  polished . Duty  Free 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


181 


ELECTRO-SYNCHRONISM-DRIVEN  RECORDING  FORK 


Nos.  51-135  to  61-140 

Patent  Pending 


In  our  electro-synchronism-driven  tuning  fork  we  believe  that  improvements  of  the  greatest  importance  have 
been  made  in  the  fundamental  instrument,  improvements  which  will  give  the  closest  approach  to  an  ideal  fork.  In 
our  method,  an  especially  designed  Microphone  is  mounted  on  the  base  of  the  instrument.  This  Microphone  picks 
up  the  vibrations  thrown  from  the  fork,  and  in  turn  varies  the  strength  of  the  electro-magnets  which  actuate  the 
fork,  leaving  the  prongs  free  to  vibrate  unhampered  by  contacts  or  springs  such  as  were  formerly  used.  In  use  the 
binding  posts  are  connected  to  the  source  of  current,  4  cells  of  dry  battery  being  recommended. 

The  synchronism  that  takes  place  is  shown  in  a  very  striking  manner.  Starting  with  an  almost  imperceptible 
vibration,  the  fork  gradually  reaches  its  highest  amplitude,  when  it  will  continue  to  give  forth  a  tone  of  great  purity, 
with  absolute  freedom  from  all  other  foreign  sounds  or  vibrations  which  have  proved  so  troublesome  in  forks  con¬ 
structed  by  ordinary  methods.  The  synchronism  method  insures  the  fork  giving  its  actual  tone,  a  result  not  ob¬ 
tained  by  any  other  method. 

Electrically  Driven  Tuning  Forks  in  which  the  electric  contact  is  made  directly  on  the  prongs  either  by  a  spring 
attached  to  one  prong  or  by  a  platinum  contact  soldered  to  it,  have  the  following  objections:  — 

1.  The  prong  of  the  fork  carrying  the  contact  or  spring  is  dampened,  and  the  fundamental  tone  of  the  fork  is 
radically  changed  thereby. 

2.  The  vibration  of  the  fork  is  forced  to  an  unnatural  pitch  by  means  of  the  sudden  rush  of  current  due  to  its 
intermittent  contact. 

3.  The  contact  point  emits  a  sound  often  sufficient  to  obscure  the  fundamental  tone  of  the  fork. 

4.  An  adjustment  that  will  give  the  natural  clear  tone  of  the  fork  is  impossible,  owing  to  the  unavoidable  noise 
due  to  this  method  of  vibration. 

In  the  Electro-Synchronism-Driven  Tuning  Fork  we  justly  claim  the  following  features:  — 

1.  The  fork  has  nothing  to  carry. 

2.  The  vibration  is  absolutely  dependent  upon  the  natural  period  of  the  fork. 

3.  There  are  no  parts  of  the  apparatus  to  take  up  vibrations  and  give  any  undesirable  sounds. 

4.  The  fork  is  actuated  by  a  current  that  varies  in  strength  from  maximum  to  minimum  in  absolute  synchronism 
with  its  own  period. 

5.  The  vibrating  apparatus  is  absolutely  distinct  and  unattached  to  the  fork  and  hence  produces  no  distortion 

I1  in  vibration. 

As  the  principal  object  of  this  apparatus  is  to  maintain  for  a  considerable  period  a  uniform  tone  and  vibration 
coming  from  a  fork  having  a  definite  vibration  period,  we  list  the  apparatus  designed  for  adjusted  forks  of  128  and 
■  256  vibrations.  We  desire  to  call  particular  attention  to  the  fact  that  these  forks  are  of  the  best  quality,  furnished 

us  by  a  prominent  European  manufacturer.  , 


61-135  ELECTRO-SYNCHRONISM-DRIVEN  RECORDING  FORK,  including  base  and  imported  fork 

No.  61-106,  35  centimeters  long,  128  VPS . ?17.25 

51-137  - ,  same  as  above,  but  with  No.  51-75  fork,  22  centimeters  long,  256  VPS .  9.50 


61-140 


UNADJUSTED  TUNING  FORK,  large  size,  for  use  with  No.  51-136.  It  is  frequently  desirable 
to  use  an  electrically  driven  tuning  fork  designed  so  that  the  stylus  for  recording  the  vibrations 
on  a  moving  surface  may  be  attached;  also  one  in  which  the  mirrors  for  use  in  tracing  Lissajous’ 
figures  may  be  used.  Where  these  attachments  are  added  the  absolute  vibration  of  the  fork 
cannot,  of  course,  be  depended  upon,  since  the  prong  must  carry  a  load.  For  this  work,  there¬ 
fore,  a  fork  which  has  not  been  especially  adjusted  is  entirely  adequate.  The  fork  which  we 
furnish  under  this  number  is  one  of  unusually  substantial  construction,  approximately  15  inches 
long,  giving  about  100  vibrations  per  second  and  supplied  with  threaded  holes  on  the  ends  of 
the  fork  for  carrying  binding  screws  which  hold  the  recording  stylus,  also  for  carrying  the  mirrors 
listed  below,  used  in  Lissajous’  experiments  .... 

Complete  with  stylus . 


6.75 


61-141  - ,  small  size  for  use  on  No.  51-137 


1.35 


61-142  MOUNTED  MIRRORS  FOR  LISSAJOUS’  CURVES  supplied  with  threaded  stems  fitting  the 

holes  of  the  fork  No.  61-140  . . Per  Pair  2.50 


i82 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  » 


61-150 


61-166 

61-167 

61-169 

61-161 


Nos.  51-160  to  51-161 


LARGE  MOUNTED  TUNING  FORKS,  most  careful  workmanship,  highest  accuracy,  mounted 
on  synchronized  resonant  cases.  Set  includes  four  large  forks  from^C1  =  256  VPS.  to  C2  =  512 
VPS.,  each  mounted  on  a  separate  case.  With  rubber  hammer  . Duty  Free 


ABOVE  FORKS  SEPARATELY  LISTED 


LARGE  MOUNTED  TUNING  FORK,  C1  =  256  VPS . Duty  Free  .  .  . 

- ,  E  =  320  VPS . Duty  Free  .  .  . 

- ,  G  =  384  VPS . Duty  Free  .  .  . 

— — ,  C2  =  512  VPS . Duty  Free  .  .  . 


51-175 

61-180 

51-190 


61-192 


If 


No.  51-180 


LARGE  MOUNTED  TUNING  FORKS,  same  quality  as  above.  Set  of  eight  forks,  giving  the 

Octave,  C1  =  256  VPS.  to  C2  =  512  VPS.,  each  mounted  on  resonant  case . Duty  Free 

- ,  same  as  above,  set  of  thirteen,  from  C1  =  256  VPS.  to  C2  =  512  VPS.;  each  mounted  on 

synchronized  resonant  case  . . Duty  Free 


SYMPATHETIC  TUNING  FORKS 

for  showing  sympathetic  vibrations, 
also  “beats.” 

Consists  of  a  pair  of  large  tuning  forks, 
accurately  adjusted  to  256  VPS.  per 
second,  mounted  on  separate  syn¬ 
chronized  resonant  cases.  One  of 
the  forks  is  supplied  with  a  slide  to 
destroy  the  unison  to  show  “beats.’’ 
Complete  with  large 
rubber  hammer, 

Duty  Free . 

- ,  extra  large,  same 

quality  as  above,  but 
accurately  adjusted 
forks  of  128  VPS., 

Duty  Free . 


No.  61-190 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


183 


THE  MORSE  SYMPATHETIC  VIBRATION  APPARATUS,  for  the  study  of  sympathetic  vibra¬ 
tions  in  simple  pendulums  and  for  determining  under  what  conditions  two  bodies  will  vibrate  in 
sympathy.  The  apparatus  clearly  shows  what  is  meant  by  the  expression,  “natural  period  of 
swing.” 

The  apparatus  consists  of  a  tripod  stand  on  which  is  mounted  the  vibration  apparatus  consisting  of 
four  simple  pendulums  in  bi-filar  suspensions  and  a  compound  pendulum  with  adjustable  disc 
bob,  all  suspended  from  a  common  swivel  support. 

If  the  compound  pendulum  is  set  vibrating  the  simple  pendulum  the  vibration  period  of  which 
is  synchronous  will  begin  to  vibrate. 

Apparatus  complete  with  tripod  stand .  $8.40 

- ,  same  as  above  but  without  tripod  stand  and  support  .  5.26 

CHEMICAL  HARMONICON  or  SINGING  FLAME,  showing  that  the  air  in  an  open  tube  may 
be  made  to  give  a  sound  by  means  of  a  luminous  jet  of  gas. 

The  apparatus  consists  of  a  tube  about  2  centimeters  in  diameter  of  the  carefully  calculated  length 
to  respond  to  the  jet  or  the  burner,  also  supplied  with  the  apparatus. 

Tube  complete  with  burner .  2.60 

CHEMICAL  HARMONICA,  similar  to  No.  61-210,  but  designed  to  sound  the  chord. 

The  apparatus  consists  of  four  tubes  similar  in  design  to  No.  61-210,  but  all  mounted  on  a  common 
stand  with  special  burner. 

Complete  as  illustrated .  14.60 

GLASS  WHISTLE  WITH  SLIDING  PISTON  for  determining  the  “fundamentals”  of  closed  pipes. 

This  consists  of  a  glass  tube  in  which  is  a  sliding  piston  and  to  which  is  fastened  a  second  tube  in 
such  a  position  that  air  blown  through  it  will  cause  the  air  column  in  the  first  tube  to  emit  a  tone 
which  may  be  proved  the  “fundamental”  of  the  tube .  1.26 


61-206 


61-206 

61-210 

61-212 

61-250 


184 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


61-240  GALTON’S  WHISTLE  for  determining  the  highest  limit  of  audibility,  —  calculated  vdbrations 
up  to  85,000  per  second  possible. 

This  is  an  accurately  constructed  instrument,  all  dimensions  calculated  to  a  scientific  nicety.  Each 
part  is  carefully  fitted,  neatly  polished,  and  lacquered.  Results  possible  fully  warrant  its  expense. 

61-243  GALTON’S  WHISTLE  for  determining  the  upper  limit  of  audibility. 

This  instrument  is  similar  in  appearance  to  No.  61-240,  but  designed  and  constructed  by  Dr.  M. 
Th.  Edelmann.  It  has  an  improvement  in  form  of  a  double  adjustment  and  a  large  throat.  It 
attains  the  highest  degree  of  accuracy  and  is  handsomely  finished  throughout.  Complete  direc¬ 
tions  and  valuable  data  are  furnished  with  each  instrument. 

Enclosed  in  leather  case . Duty  Free 

61-276  ALL  METAL  ORGAN  PIPES,  set  of  four  giving  the  Chords,  C\  E,  G,  and  C2. 

These  pipes  are  carefully  constructed  from  metal,  and  from  actual  experimentation  are  found  to  give 
the  best  results,  far  in  excess  of  pipes  constructed  of  wood.  They  are  especially  constructed  for 
us  and  we  have  added  to  their  pedagogic  value  by  the  attachment  of  a  Sliding  Tuning  Tube  which 
is  designed  to  change  the  tone  by  lengthening  the  tube. 

These  pipes  will  be  found  a  valuable  addition  to  any  laboratory  and  their  handsome  appearance  will 
certainly  add  to  the  appearance  of  the  scientific  equipment  . w . 

61-286  -  — ,  same  as  above,  but  a  full  set  of  eight  pipes  sounding  the  octave  from  C1  to  C2 . 

61-290  DEMONSTRATION  ORGAN  PIPE  for  showing  the  vibrating  segments  and  nodes  of  an  organ 
pipe  by  means  of  a  membrane. 

This  consists  of  a  wooden  pipe,  one  side  of  which  is  of  glass.  Fitting  within  this  pipe  is  an  adjust¬ 
able  membrane,  the  height  of  which  in  the  tube  can  be  regulated  by  means  of  a  rod  to  which  the 
membrane  is  attached. 

On  lowering  the  membrane,  in  the  tube,  until  it  reaches  a  node,  a  pure  tone  is  produced;  but  on 
raising  or  lowering  the  membrane  a  few  centimeters,  a  harsh  note  is  given  out.  On  covering 
the  membrane  with  a  little  sand  or  cork  dust  and  changing  its  height  in  the  tube,  it  will  be  seen 
that  the  sand  or  dust  is  disturbed  at  all  positions  except  at  the  nodes . 

61-295  DEMONSTRATION  ORGAN  PIPE  WITH  MOVABLE  STOP  for  sounding  two  octaves  with  tones 

and  semi-tones  distinctly  marked  on  the  frame  which  operates  the  stop  . . 


$9.85 


16.60 


9.60 

18.76 


4.00 


4.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


185 


61-310J  MOUNTED  TUBE  for  showing  transmission  of  sound  by  liquids. 

This  apparatus  consists  of  a  glass  tube  with  funnel-shaped  open  end,  mounted  on  resonant  case. 
If  stem  of  vibrating  fork  is  held  at  open  end  it  may  be  shown  that  no  sound  is  transmitted;  if,  how¬ 
ever,  the  tube  is  filled  with  water  and  the  stem  touches  the  surface  of  the  liquid,  sound  is  trans¬ 
mitted . Duty  Free 


No.  51-315 

61-316  XYLOPHONE  showing  musical  tones  from  vibrating  wooden  bars.  Consists  of  fifteen  maple  bars 
mounted  on  wood  frame  and  accurately  tuned  to  sound  two  octaves.  With  two  hammers  .  . 

61-320  METALAPHONE  for  showing  musical  tones  emitted  by  vibrating  metal.  Consists  of  twelve  metal 
plates’carefully  tuned  and  mounted  in  ornamented  wooden  frame.  With  two  hammers  .... 


No.  61-325 


$8.60 


$1.25 

1.25 


51-325  TUBEPHONE  showing  musical  tones  emitted  by  vibrating  tubes.  Consists  of  fifteen  brass  tubes 

highly  polished,  mounted  in  wooden  frame.  With  two  hammers,  in  cardboard  box . $1.95 


i86 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


REFLECTION,  REFRACTION  AND 
INTERFERENCE  OF  SOUND  WAVES 


No.  52-10 


62-10  THIRTEEN-INCH  UNIVERSALLY  ADJUSTABLE  TRUE  PARABOLIC  REFLECTORS  for  dem¬ 
onstrating  Reflection  of  Sound,  Heat  and  Light  Waves. 

In  offering  for  sale  our  Improved  Reflectors  we  desire  to  emphasize  the  TRUE  PARABOLIC  SUR¬ 
FACES.  The  curves  of  these  surfaces  have  been  accurately  calculated  and  drawn  and  then  by 
painstaking  processes  a  chuck  has  been  turned  to  the  true  parabolic  curve.  Our  Reflectors  are 
all  spun  from  this  chuck.  The  reflecting  surface  is  then  highly  polished  and  heavily  nickel-plated, 
presenting  an  excellent  surface  without  waves. 

The  Reflectors  are  mounted  in  a  two-part  circular  casting  in  such  a  manner  as  to  entirely  obviate  any 
danger  of  distorting  the  surfaces.  This  two-part  casting  is  brought  together  at  the  bottom,  where 
it  makes  a  swivel  junction  with  a  rod  which  telescopes  into  the  supporting  base. 

The  holders  and  attachments  are  all  of  special  design  which  allows  of  both  coarse  and  fine  adjustments. 
We,  therefore,  secure  a  tilting  movement  for  the  Reflectors,  an  adjustment  for  proper  height,  and 
universal  movements  for  each  attachment. 

In  illustrating  Reflection  of  Sound  a  simple  experiment  is  possible  by  attaching  a  watch  to  one  of 
the  carriers  at  the  focus  of  one  reflector;  if  now  one  end  of  a  flexible  tubing  is  placed  at  the  focus 
of  the  other  reflector  attached  to  the  carrier  and  the  other  end  terminating  in  a  large  funnel,  mega¬ 
phone,  or  horn,  the  ticking  of  the  watch  may  be  heard  by  the  majority  of  the  class. 

The  finish  of  this  instrument  is  fully  in  keeping  with  the  design.  The  outer  surfaces  of  the  Reflec¬ 
tors  are  dull  oxidized,  the  H  Base  bright  japan,  and  all  brass  parts  polished  and  nickel-plated. 

Thirteen-Inch  Universally  Adjustable  True  Parabolic  Reflectors  complete  as  illustrated  with  at¬ 


tachments  .  Per  Pair  $17.60 

52-16  - ,  same  as  above,  mounted  on  stand  but  without  attachments  or  carriers .  Per  Pair  13.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


187 


52-30  SOUND  LENS,  for  experiments  on  the  refraction  of  sound. 

The  apparatus  consists  of  a  double-walled  rubber  diaphragm 
re-inforced  by  a  rolled  metal  ring  and  provided  with  an 
outlet  for  inflating  with  gas,  refractive  power  of  which  is  to 
be  studied.  This  outlet  is  also  convenient  for  regulating 
the  curvature  and  hence  the  refractive  power  of  the  lens. 

A  source  of  sound  is  placed  in  the  direction  of  the  axis;  the 
point  is  then  sought  on  the  other  side  of  the  lens  at  which 
the  sound  is  most  distinctly  heard.  This  point  will  be  the 
focus,  and  at  all  other  points  the  sound  is  scarcely  per¬ 
ceptible,  showing  that  sound  has  been  refracted  by  the  lens 
in  much  the  same  way  as  light  is  refracted  by  a  glass  lens. 

This  apparatus  is  supported  by  a  simple  and  effectively J[  de¬ 
signed  base  and  supporting  arm  so  arranged  as  to  give 
ample  adjustment  and  full  range  in  the  angle  of  inclination. 

Sound  Lens  complete,  with  stand,  as  illustrated .  $9.80 

62-32  SOUND  LENS  only,  ready  for  mounting  on  stand  ....  6.75 

62-40  EAR  TRUMPET,  for  concentrating  sound  waves.  This|is  a 
neatly  finished  metal  instrument  designed  to  reflect  and 
concentrate  sound  waves .  2.60 


No.  62-30 


62-76  KUNDT’S  INTERFERENCE  APPARATUS  for  the  quantitative  study  of  Interference  of  Sound 
Waves. 

This  apparatus  consists  of  two  U-shaped  nickel-plated  brass  tubes,  one  provided  with  supporting 
cross  bars;  the  other  has  both  arms  graduated,  telescoping  into  the  first.  To  one  of  the  parallel 
sides  of  this  interference  tube  is  attached  a  closed  glass  tube  which  in  use  contains  cork  dust  or 
lycopodium  powder.  To  the  other  side  is  attached  a  glass  tube  with  supported  sliding  piston.  In 
use,  vibrations  are  set  up  in  the  piston  tube  with  the  movable  telescoping  part  of  the  interference 
tube  pushed  home,  then  with  this  part  so  that  it  represents  1,  2,  3,  4,  5,  etc.  quarter  wave-lengths. 

It  will  be  noted  that  figures  are  produced  with  the  even  numbers  and  are  not  formed  with  the  odd 
numbers  of  quarter  wave-lengths.  Mounted  on  well  finished  wood  base . $15.00 


1 88 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  62-85 


No.  21-246 


62-80  INTERFERENCE  TUBES  after  QUINCKE  for  use  with  C1  =  512  VPS.,  in  illustrating  interference 

of  sound  waves. 

The  apparatus  consists  of  two  T-shaped  glass  tubes  of  equal  diameter  connected  as  illustrated  by 
rubber  tubing. 

If  a  tuning  fork  is  sounded  before  the  open  end  of  the  long  tube,  and  the  open  end  of  the  other  tube  is 
held  to  the  ear,  there  will  be  no  sound  heard  providing  the  length  of  the  tube  connecting  the  branches 
of  the  T-tube  is  one-half  the  wave-length  of  the  note  produced  by  the  fork.  If,  however,  this 
rubber  tube  be  closed  by  pinching  it,  the  note  is  at  once  heard. 

Complete  with  rubber  tubing  as  illustrated .  $0.90 


62-86  HOPKINS’  METAL  FORK  TUBE  after  Gage’s  “Introduction  to  Physical  Science,”  Exp.  255,  for 
study  of  interference  with  a  Chladni’s  Plate  (see  Nos.  54-126  and  64-134). 

This  consists  of  a  forked  metal  tube  with  adjustable  extension.  • 

In  use,  the  plate  is  bowed  so  that  the  two  diagonals  are  distinctly  formed.  If  the  fork  of  the  Inter¬ 
ference  T  ube  is  held  over  two  non-contiguous  sectors,  the  sand  strewn  on  the  membrane  is  violently 
agitated.  If  the  fork  is  held  over  two  contiguous  sectors,  the  sand  is  not  disturbed .  3.16 


No.  53-40 


21-225  SAVART’S  WHEEL,  COLOR  AND  SIREN  DISC  combined.  (See 

Section  21.) .  1.50 

21-240  SAVART’S  WHEEL  for  use  on  Rotator,  consisting  of  four  discs  of 
metal  in  the  periphery  of  which  are  cut  teeth,  the  number  forming 
a  simple  ratio  to  give  a  harmonic  chord .  2.36 

21-242  SAVART’S  WHEEL,  a  single  disc  for  attachment  to  Rotatqr  .  .  .  .48 

21-245  SAVART’S  WHEEL  for  demonstrating  that  pitch  is  proportional  to 
the  number  of  vibrations  per  second. 

The  apparatus  consists  of  a  heavy  cast  toothed  wheel  mounted  on  steel 
pinions  in  a  forked  stand.  This  wheel  may  be  rotated  by  means  of 
a  cord.  If  a  card  is  held  lightly  against  the  teeth  of  the  wheel  dur¬ 
ing  rotation,  a  note  wall  be  sounded,  the  pitch  depending  on  the 
speed  of  the  wheel  .  7.66 

53-40  CAIGNARD-LATOUR  SIREN  WITH  COUNTERS.  This  is  a  care¬ 
fully  constructed  scientific  instrument,  a  product  of  a  firm  well 
known  in  Europe  for  accurate  designs  of  acoustical  apparatus.  It 
is  handsomely  finished  throughout  . Duty  Free  .  .  . 

63-42  CAIGNARD-LATOUR  SIREN  WITHOUT  COUNTERS.  This  in¬ 
strument  is  similar  in  design  to  the  one  above  but  without  counters. 

Duty  Free  .  .  . 


63-46  DEMONSTRATION  CAIGNARD-LATOUR  SIREN  WITHOUT  COUNTERS.  This  is  a  greatly 

simplified  form  of  the  above .  . 


9.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


189 


SONOMETERS 

Our  Sonometers  are  made  from  selected  well  seasoned  wood  very  carefully  glued  up  and  finely  finished.  We 
list  below  only  those  designs  which  have  in  actual  use  given  the  most  efficient  service.  Each  sonometer  is  sup¬ 
plied  with  wires  and  necessary  bridges.  On  each  case  beneath  the  wires,  there  is  a  metric  scale  on  which  is  also 
indicated  the  lengths  of  strings  necessary  to  give  both  the  Diatonic  and  the  Equally  tempered  scale  between  C  = 

256  VPS.  and  C  =  1024  VPS. 


No.  63-100 


No.  63-116 


63-100 


63-101 

63-102 

63-116 


63-117 

63-126 

63-127 

63-136 

63-137 

63-138 

63-139 


No.  63-136 


SONOMETER.  This  sonometer  is  complete  as  illustrated,  requiring  no  accessory 
weights,  scale  pans,  etc.  Tension  is  caused  by  dynamometers,  fine  adjustment 
of  tension  being  secured  by  turning  the  wing  nut  sat  the  end  of  the  slow  motion 
screws  to  which  the  wires  are  attached.  Length  meters  over  all.  Complete 


as  illustrated .  ?8.15 

- ,  without  dynamometers .  4.86 

SONOMETER  WIRES,  set  of  three  wires  as  used  in  above . Set  .20 


NATIONAL  THREE  WIRE  SCHOOL  SONOMETER  after  Turner  and  Hersey, 

Exp.  No.  S040.  Requires  no  accessory  weights,  scale  pans,  etc.  Three  wires 
attached,  each  with  tension  spring  of  25  pounds  capacity.  Fine  adjustment  of 
tension  secured  by  piano  tension  keys .  4.60 

SONOMETER  WIRES,  set  of  three  as  used  in  No.  63-116 . Set  .20 

VERTICAL  WALL  FORM  SONOMETER.  Recommended  in  that  it  takes  little 
space  and  that  the  tension  is  applied  direct.  With  two  wires,  bridge  clamps, 
etc.,  as  illustrated,  but  without  hangers  and  weights . 11.50 

SONOMETER  STRINGS,  0.014  and  0.028  inch  diameter  as  used  on  above  Sono¬ 
meter  . Pair  .35 

LEVER  TENSION  SONOMETER.  Tension  adjusted  by  weights  sliding  on  levers, 

fine  adjustment  by  tension  keys.  Without  weights .  7.80 

DIRECT  TENSION  SONOMETER.  Tension  secured  by  means  of  weights  to  be 

attached  to  cords  over  freely  running  pulleys.  Without  weights .  7.80 

DIRECT  TENSION  SONOMETER,  similar  to  above,  but  with  tension  keys  and 

complete  with  necessary  hangers  and  weights . 10.60 

KEY  TENSION  SONOMETER.  Tension  secured  by  Keys  only .  7.25 


No.  63-125 


igo 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


53-200 


61-75 

53-205 


63-216 


63-225 


RESONANCE  TUBES 


No.  53-200 


No.  63-206 


KNOTT’S  ONE  HUNDRED  AND  FIFTY  CENTIMETER  RESONANCE  APPARATUS,  for 

determining  the  wave  length  of  a  tuning  fork;  also  for  determining  the  velocity  of  sound  in  air. 

The  apparatus  consists  of  a  metal  upright  with  metric  scale  mounted  on  our  H-base.  To  the  rods 
of  this  upright  are  attached  the  clamps  for  holding  the  required  accessories.  Thus  the  resonant 
tube  is  supported  at  the  left  by  Nos.  5-887  and  6-089  Clamps,  and  the  reservoir  at  the  right  by 
No.  6-885  Clamp,  the  fork  at  the  top  by  one  each  of  our  Nos.  6-450  and  6-891  Clamps.  The 
apparatus  is  designed  to  support  a  tube  of  sufficient  dimensions  so  that  with  a  C1  =  256  VPS. 

Fork  a  resonating  column  of  of  a  wave  length  is  possible. 

Apparatus  neatly  finished  throughout,  complete  as  illustrated  but  without  fork .  $8.60 

TUNING  FORK,  C1  =  256  VPS .  1.20 

FIVE-FOOT  METAL  RESONANCE  TUBE  WITH  WATER  LEVEL  INDICATOR,  for  determin¬ 
ing  the  Velocity  of  Sound  in  Air;  also  for  determining  the  Wave  Length  of  a  Tuning  Fork. 

This  is  a  metal  tube,  five  feet  in  height,  mounted  on  our  H-base.  At  the  lower  end  of  this  tube  is 
a  lateral  tube  with  stop-cock,  which  can  serve  either  as  an  inlet  or  as  an  outlet  tube  as  may  be 
desired.  A  glass  tube  of  the  same  length  as  the  metal  tube  connected  to  this  lateral  tube  serves 
as  an  indicator  for  registering  the  length  of  the  resonating  air  column. 

This  design  combines  advantages  of  other  types,  and  has  the  further  feature  of  facility  of  measure¬ 
ments  of  air  columns,  ease  in  varying  height  of  water  level,  and  extreme  durability .  6.25 

ONE  HUNDRED  AND  FIFTY  CENTIMETER  RESONANCE  APPARATUS,  after  Ames  &  Bliss’ 
“Manual  of  Experiments  in  Physics,”  Experiment  40. 

This  apparatus  consists  of  a  long  glass  tube  with  a  small  side  tube  attached  near  the  open  end, 
the  bottom  of  which  is  tapered  so  as  to  join  with  a  length  of  rubber  tubing  connected  either  with 
the  water  tap  or  as  illustrated  with  a  reservoir  for  water. 

This  apparatus  is  mounted  as  illustrated  on  a  supporting  stand,  as  described  above. 

Complete  as  illustrated,  but  without  tuning  fork .  9.26 

CULLER’S  RESONANCE  APPARATUS,  without  support . 81 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


191 


53-230 

63-235 


31-250 


No.  63-230 


HORIZONTAL  RESONANCE  TUBE,  for  measuring  the  velocity  of  sound  in  air. 

This  is  a  glass  tube  mounted  horizontally  on  a  convenient  wooden  support.  It  is  provided  with  a 
sliding  piston  for  regulating  the  length  of  the  active  air  column.  This  will  be  found  a  convenient 

students’  apparatus . 

GLASS  RESONANCE  TUBES,  with  smooth  ends,  for  use  in  resonance  experiments. 


a 

Length,  centimeters . -  55 

Diameter,  centimeters  ....  3.5 

Each . $0.85 


b  c 

110  110 

3.5  4 

1.20  1.90 


RESONANCE  GLASS  JARS,  for  use  in  resonance  experiments.  These  jars  are  of  clear  white  glass, 
with  foot  and  rim. 


a  b  c  d  e 

Size,  inches  .  :  .  12  X  \]/2  12X2  15X2  15X3  18X3 

Each .  $0.50  .65  .80  1.00  1.35 


$2.25 


STUDY  OF  SOUND  VIBRATIONS 

RECORDING  APPARATUS  -LISSAJOUS’  CURVES— CHLADNI’S  PLATES 
MANOMETRIC  FLAME  APPARATUS— SONOGRAPH 

GRAPHIC  REPRESENTATION  OF  SOUND 


64-16  KNOTT’S  UNIVERSALLY  ADJUSTABLE  VTBROGRAPH,  for  determining  the  vibration  frequency 
of  a  tuning  fork. 

The  results  of  experience  have  demonstrated  that  a  Vibrograph  built  of  wood  has  many  objection¬ 
able  features.  We  have,  therefore,  discarded  wood  altogether  in  this,  our  new  design.  Two 
nickel-plated  rods  held  firmly  in  end  supports  form  the  track  along  which  the  carriage  bearing  the 
smoked-glass  plate  moves  freely.  An  upright  fastened  to  one  track  bears  the  rod  to  which  is 
fastened  the  clamp  supporting  the  pendulum.  The  tuning  fork,  to  one  prong  of  which  must  be 
fastened  a  bristle,  is  clamped  as  pictured  at  left  of  illustration  in  a  frame  which  is  adjusted  by  means 
of  a  thumb  nut  and  which  in  turn  adjusts  the  plane  of  the  fork. 

In  addition  to  the  substantiality  of  this  design,  our  claims  for  accuracy  with  a  minimum  of  trouble 
are  fully  warranted.  The  handsome  appearance  of  the  instrument  will  enhance  its  value  as  an  ac¬ 
quisition  in  any  well-equipped  laboratory. 

Complete  as  illustrated,  but  without  fork  „. .  $4.00 

64-16a  COATED  PAPER.  A  special  coated  paper  has  been  provided  for  use  on  above  Vibrograph.  This 
paper  has  the  property  of  turning  dark  whenever  rubbed  by  brase,  aluminum  or  similar  metals. 

It  will  be  found  valuable  in  making  permanent  records . Per  Package  of  25  Sheets  .16 

64-16  VIBROGRAPH  TUNING  FORK  with  stylus,  low  pitch,  large  amplitude .  1.35 

54-17  EXTRA  GLASS  PLATES,  for  use  with  above  VIBROGRAPH . Each  .06 

64-26  BRISTLE  STYLUS  AND  FIXATIVE,  for  use  on  a  Tuning  Fork  when  it  is  desired  to  record  the 

vibrations  on  a  smoked  or  coated  plate  or  drum .  .25 


192 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


VARIABLE  SPEED  AND  MULTIPLE  RECORDING  KYMOGRAPHS  AND 

RECORDING  DRUMS 

With  Invisible  Non-Projecting  Thread  Feed 


Nos.  64-30,  64-36  and  61-76 

Patent  Pending 


No.  54-40 


It  has  been  our  purpose  in  this  design  to  produce  an  instrument  capable  of  a  great  variety  of  uses  and  of  the 
very  highest  grade.  It  may  be  obtained,  operated  either  by  clock  movement  or  arranged  for  both  hand  and  belt 
drive. 

The  cylinder  is  12 yi  centimeters  in  diameter  by  16>£  centimeters  long,  and  has  a  lateral  movement  of  16  centi¬ 
meters  on  a  screw  with  thread  so  cut  and  mounted  that  the.  shaft  does  not  extend  beyond  the  bearings  more  than  is 
shown  in  the  illustration. 

Ample  room  is  provided  for  the  simultaneous  use  of  four  tuning  forks  or  six  recording  pens.  One  may,  there¬ 
fore,  make  records  of  six  different  operations,  no  matter  where  located. 

Features,  — 

1.  Frictionless  rollers  on  which  the  shaft  is  rotated. 

2.  The  cylinder  is  mounted  so  that  it  may  be  given  a  revolving  and  horizontal  movement  along 

the  shaft  without  the  shaft  extending  beyond  the  bearings  more  than  is  shown  in  the 

illustration. 

3.  The  upright  supports  are  adjustable  forward  and  backward  on  a  lathe  rest  support. 

4.  Vertical  adjustment  is  simplified  by  means  of  a  clamp  and  a  series  of  notches  in  the  uprights 

giving  a  rigidity  and  range  not  found  in  any  other  instrument  of  this  class. 

5.  Screws  of  different  pitches  may  be  obtained  for  the  purpose  of  adapting  the  forward  movement 

to  the  nature  of  the  record  desired. 

64-30  VARIABLE  SPEED  KYMOGRAPH  with  Clock  Drive  and  Invisible  Feed.  With  this  clock  drive 

two  speeds  are  possible,  the  change  secured  by  meshing  gears  in  or  out,  —  one  revolution  in 

,  twenty-four  hours  or  one  in  twelve  hours.  Clock  movement  is  a  standard  high  grade  eight-day 

movement  especially  adapted  to  this  kymograph.  Without  tuning  fork  and  marker . $47.50 

54-32  VARIABLE  SPEED  KYMOGRAPH  for  both  Hand  and  Belt  Drive.  Speed  may  be  regulated  within 

the  limit  of  the  motor  or  of  the  relative  sizes  of  the  pulleys.  Without  tuning  fork  and  marker  .  .  35.00 

64-35  KYMOGRAPH  TIME  MARKER.  This  marker  is  much  the  same  as  ordinarily  supplied  for  Kymo¬ 
graph  work  and  is  modified  to  the  extent,  only,  of  securing  a  better  continuous  record .  6.50 

54-37  KYMOGRAPH  RECORD  SHEETS  for  use  with  Nos.  64-30  and  64-32  Kymographs.  Divisions 

represent  ten  or  five-minute  intervals . Per  Fifty  2.35 

TUNING  FORKS,  —  any  form  under  ten  inches  long.  See  Section  51.  • 

54-40  CLOCK  RECORDING  KYMOGRAPH.  This  instrument  was  designed,  at  the  request  of  Dr.  Bovie 
of  Harvard  University,  to  provide  a  simple  easily  manipulated,  effective  device  for  recording  the 
curve  of  plant  growth  in  conjunction  with  the  Bovie  Auxanometer. 

The  recording  mechanism,  whether  it  be  a  pencil  or  electrical  pen,  is  readily  clamped  to  the  sup¬ 
porting  upright  as  indicated  in  the  illustration.  The  clock  mechanism  mounted  in  the  base  is  a 
standard  twenty-four  hour  clock  movement  of  heavy  construction. 

The  cylinder  is  raised  to  the  upper  position  by  simply  releasing  the  compression  clamp  and  lifting  the 
cylinder  bodily.  The  range  of  movement  and  the  length  of  the  cylinder  is  such  as  to  permit  three 
or  four  records  being  made  at  one  time.  This  is  made  possible  because  of  the  position  in  which 
the  cylinder  is  mounted,  the  weight  of  the  cylinder  assisting  rather  than  retarding  the  clock  move¬ 
ment. 

Complete  with  twenty-four-hour  movement . 22.25 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


193 


LISSAJOUS’  CURVES  APPARATUS 


# 


No.  54-50 


64-60  LISSAJOUS’  CURVES  APPA¬ 
RATUS,  IMPROVED  MODEL, 

for  demonstrations  of  parallelly 
and  vertically  combined  vibra¬ 
tions. 

Mounted  on  a  heavy  metal  base  are 
the  supports  for  the  fork  hold¬ 
ers, —  one  to  support  the  fork  in 
a  horizontal  position  and  the 
other  two  in  a  vertical  position, 
one  of  the  latter  capable  of  being 
turned  backward  and  forward 
by  means  of  a  small  crank. 

The  forks  supplied  with  the  appa¬ 
ratus  are  250  millimeters  in 
length  and  have  a  vibration  fre¬ 
quency  of  128  V.P.S.  They  are 
substantial  in  structure  and 
especially  designed  to  give  a  con¬ 
tinuous  vibration  of  large  am¬ 
plitude.  Each  fork  is  kept  in  vi¬ 
bration-fey  electro-magnets  with 
which  each  carrier  is  supplied. 
By  means  of  two  riders  which 
are  furnished  with  the  appara¬ 
tus  the  pitch  of  a  fork  can  be 
slightly  changed  for  causing 
beats. 

With  addition  of  a  Projection  Lan¬ 
tern  and  a  Lens,  the  curves  can 
be  projected  very  beautifully  on 
a  screen. 

Apparatus  complete  with  two 
forks . Duty  Free 


54^65  LISSAJOUS’  CURVES  APPARATUS,  same  as  above,  but  without  the  movable  upright  and  crank 
adjustment.  Complete  with  two  forks . Duty  Free 

Luminous  images  on  the  screen  when  the  Tuning  Forks  are  in  unison. 


0  H  X  Vs  '  V  Vs  X  Vs  1 

Luminous  images  when  the  difference  between  the  Tuning  Forks  is  an  octave. 


194 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


Y  PENDULUM  (SAND  PENDULUM).  This  pendulum 
consists  of  a  heavy  bob  suspended  by  two  cords,  slid¬ 
ing  along  which  is  a  small  brass  ring  the  office  of  which 
is  to  vary  the  length  of  the  stem  of  the  Y,  thus  modify¬ 
ing  the  conditions  upon  which  the  relative  phases 
and  amplitudes  depend.  As  this  bob  vibrates,  fine 
sand  contained  in  the  funnel-shaped  reservoir  is  al¬ 
lowed  to  trickle  forth,  thus  tracing  the  path  of  the  vi¬ 
brating  pendulum. 

If  the  bob  vibrates  in  the  plane  of  the  paper,  the  effec¬ 
tive  length  is  from  the  adjustable  brass  ring  to  the 
bob;  if  it  vibrates  at  right  angles  to  this  plane,  it  is  the 
distance  from  the  support  rod  to  the  bob.  The  periods, 
therefore,  will  be  different  and  independent.  By  ad¬ 
justing  the  two  lengths  by  means  of  the  ring,  the  bob 
may  be  made  to  describe  various  Lissajous’  Figures. 

Y  Pendulum  only  without  support  of  any  kind  .... 


FIGURES  APPARATUS 


Nos.  54-126  to  54-134 


Nos.  5-1000  and  5-1085 


No.  54-142 


$0.90  . 


Vibrating  Plates  contain  nodal  lines  which  vary  in  number  and  position  according  to  the  form  and  size  of  the 
plate  and  the  point  at  which  they  are  set  in  vibration.  We  list  below  two  forms  of  plates,  each  form  in  two  sizes. 
We  also  list  three  different  types  of  clamps,  either  of  which  will  be  found  well  adapted  for  use  with  any  of  the  plates. 
For  those  teachers  who  are  provided  with  T-Beam  Basic  Clamp  No.  5-1000,  Interlocking  Clamp  Attachment  No. 


6-1085  will  be  found  the  best. 

54-126  ROUND  CHLADNI’S  PLATE,  6  inches  diameter . $1.30 

54-128  - ,  10  inches  diameter .  1-66 

54-133  SQUARE  CHLADNI’S  PLATE,  6  inches  square .  1.30 

54-134  - - ,  10  inches  square .  1.66 

5-1085  CHLADNI’S  PLATE  INTERLOCKING  CLAMP  ATTACHMENT  for  use  on  our  No.  5-1000  T- 

Bearn  Basic  Clamp  “A” .  .60 

5-1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A” . 94 

54-141  CHLADNI’S  PLATE  CLAMP,  common  type . 76 

54-142  - ,  large  size  for  plates  up  to  10  inches .  1.95 

54-145  LYCOPODIUM  POWDER  for  use  in  Kundt’s  Tubes  and  on  Chladni’s  Plates.  Before  using  this 

powder,  we  recommend  that  it  be  thoroughly  dried  for  best  results.  Per  four-ounce  carton  .  .  .45 

54-147  SAND  for  use  on  Chladni’s  Plate.  This  is  the  best  quality  fine-grained  sand  carefully  sifted.  Per 

eight-ounce  carton .  .22 

57-20  DOUBLE-BASS  BOW,  recommended  for  exciting  Chladni’s  Plates .  1.36 


f 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


195 


MANOMETRIC  FLAME  APPARATUS 


No.  21-290  _JNo.  21-296 


64-166  MANOMETRIC  FLAME  APPARATUS  for  analysis  of  sound.  Composed  of  No.  21-296  Konig’s 
Manometric  Flame  Capsule  and  No.  21-299  Cubical  Mirror.  The  latter,  in  use,  must  be  at¬ 
tached  to  the  socket  of  a  rotator.  The  Manometric  Capsule  is  constructed  of  a  two-part  casting 
assembled  with  the  sensitive  diaphragm  between.  To  one  casting  is  attached  the  tube  and  mouth¬ 
piece,  to  the  other  the  jet  and  gas  tube,  the  latter  attached  to  a  base  forming  the  support.  The 
cubical  mirror  consists  of  a  metal  box  to  the  sides  of  which  are  fastened  mirror  plates.  To  the 


lower  side  of  this  box  is  attached  a  spindle  to  fit  the  socket  of  the  rotator. 

Apparatus  complete,  as  illustrated,  but  without  Rotator . $5.90 

21-290  CUBICAL  MIRROR,  as  used  in  No.  64-166  .  3.16 

21-296  KONIG’S  MANOMETRIC  FLAME  CAPSULE  complete,  as  illustrated  above .  2.76 

For  ROTATORS,  see  Section  21. 

64-180  MANOMETRIC  FLAME  APPARATUS  for  analysis  of  sound. 


This  apparatus  is  similar  to  No.  64-166,  but  of  simpler  construction.  The  revolving  mirrors  are 
set  in  brass  frame  fitted  with  spindle  for  revolving  by  hand.  A  simply  constructed  Manometric 
Flame  Capsule  is  supplied  with  rubber  tube  and  mouth-piece. 

Manometric  Flame  Capsule,  complete  with  Mirror .  4.40 


21-300  REVOLVING  MIRROR  WITH  POSITIVE  SPEED  GOVERNOR.  To  meet  the  repeated  demands 

for  a  mirror  which  may  be  revolved  at  varying 
speed  and  of  a  size  sufficiently  large  for  ordinary 
laboratory  work  we  have,  after  considerable  experi¬ 
mentation,  perfected  the  design  illustrated. 

This  mirror  is  self-contained  in  that  the  rotating 
power  is  contained  in  the  base  in  the  form  of  a 
small  motor,  with  “start”  and  “stop”  key.  We 
secure  a  positive  speed,  governed  by  means  of  a 
simple,  effectively  operating  device  noted  above 
the  mirror  shaft  and  a  centrifugal  governor 
mounted  within  the  mirror  case.  We  are  able  to 
secure  with  this  structure  speeds  varying  from  a 
few  revolutions  per  minute  up  to  2,000, — -the 
maximum  speed  of  the  motor.  This  variation  in 
speed  may  be  made  during  the  revolution  of  the 
mirror  simply  by  a  movement  of  the  screw  over 
the  axle. 

As  may  be  noted,  this  design  consists  of  a  metal 
housing  which  serves  also  as  a  substantial  base. 

Cast  to  this  housing  is  an  upright  with  project¬ 
ing  arm.  The  mirror  is  mounted  in  metal  cast¬ 
ings  carefully  centered.  The  metal  housing  is 
provided  with  binding  posts  for  connections  to 
the  motor  and  also  with  “start”  and  “stop” 

No.  21-300  key.  The  whole  is  finished  in  nickel  and  black  No.  21-300  (Sectional  View) 

oxidized,  presenting  a  handsome  appearance.  It 

will  be  found  efficient  for  all  general  work  for  which  a  rotating  mirror  is  used . $9.76 


ig6 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


GRAPHIC  ANALYSIS  OF  SOUND  WAVES 


No.  54-200 

“SONOGRAPH” 


No.  54-200 


No.  21-300 


54-200  “SONOGRAPH.”  The  instrument  above  illustrated  will  show  in  a  superior  manner  all  that  the 
manometric  flames  will  show  and,  in  addition,  many  other  interesting  experiments.  Results  are  easily  obtained, 
and  both  simple  and  complex  tones  are  readily  analyzed  into  their  various  wave  forms,  a  pure  tone  depicting  in  a 
striking  manner  the  fundamental  sine  wave. 

The  operation  of  the  “sonograph”  depends  on  the  compression  and  rarefactions  set  up  in  the  air  by  sound  — 
a  spoken  word,  a  note  from  an  organ  pipe,  a  tuning  fork,  etc.,  etc.  These  compressions  and  rarefactions  are  com¬ 
municated  to  a  diaphragm  which  is  set  in  vibration,  the  vibrations  being  greatly  magnified  by  a  small  mirror,  the 

amount  of  movement  being  indicated  by  the  tracings  of  a  spot  of  light  on  the  screen.  These  tracings  will  take  the 

form  of  waves  if  the  spot  of  light  be  first  directed  on  a  rotating  mirror.  This  rotating  mirror  should  be  placed  between 
a  lens  and  the  screen.  Our  No.  21-300,  illustrated  above,  described  in  Section  21,  has  been  especially  designed  for 

this  work.  The  speed  is  ingeniously  governed  for  either  very  high  pitch  or  very  low  pitch  without  stopping  the 

motor  which  rotates  the  mirror. 

To  secure  the  most  satisfactory  results  a  strong  source  of  light  will  be  necessary.  Sunlight  is,  of  course,  the 
best  and  when  used,  a  “pencil”  of  light  secured  through  a  small  aperture  will  be  found  most  effective.  When  a  pro¬ 
jection  lantern  or  any  strong  artificial  source  is  used,  a  system  of  lenses  should  be  provided  to  render  the  rays  paral¬ 
lel.  With  a  good  arc  light  or  light  from  the  sun,  the  waves  may  be  easily  shown  to  five  hundred  students. 

The  waves  illustrated  below  are  photographic  reproductions  taken  on  a  revolving  film. 


a  e  i  o  u 

Wave  Forms  of  Vowels. 


Wave  Form  of  Vowel  e. 

“SONOGRAPH”  only,  without  lens,  mirror,  etc . $26.00 

21-300  ELECTRICALLY  OPERATED  ROTATING  MIRROR,  designed  especially  for  use  with  “Sono¬ 
graph.”  For  description  see  Section  21 . 


975 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


197 


RESONATORS 


65-10  BELL  and  ADJUSTABLE  RESONATOR. 

The  apparatus  consists  of  a  Bell  15  centimeters  in  diameter 
which  may  be  mounted  on  a  stand.— The  Resonator  consists 
of  a  brass  tube  with  close-fitting  sliding  piston.  This  tube 
is  of  sufficient  length  to  respond  to  all  notes  above  256 
V.  P.  S. 

Complete  as  illustrated,  with  Bell,  Resonator,  and  Stand,  but 

without  plate . $3.16 


No.  65-32 


No.  65-10 


BRASS  HELMHOLTZ  RESONATORS.  These  Resonators  are  thin  brass  globes,  with  wide  orifices  at  one 
side  to  receive  the  exciting  waves  and  narrow  orifices  to  conduct  the  vibrations  to  the  ear.  They  are  accurately 
made,  neatly  polished  and  lacquered.  Fundamental  tone,  low  C  =  64  V.  P.  S. 


55- 30  HELMHOLTZ  RESONATORS,  set  of  eleven . Duty  Free  .  .  . 

66-32  -  — ,  set  of  eighteen . Duty  Free  .  .  . 

56- 34  -  — ,  set  of  twenty-five . Duty  Free  .  .  . 


No.  55-45 


65- 46  GLASS  HELMHOLTZ  RESONATORS  for  the  analysis  of  sound,  consisting  of  a  set  of  four  glass 

globes  each  with  a  wide  orifice  at  one  side  to  receive  the  exciting  waves  and  a  narrow  orifice  at  the 
other  side  to  conduct  the  vibrations  to  the  ear.  Will  respond  to  the  notes  Cs,  E4,  C4,  and  Gs  .  .  .  $11.50 

66- 60  ACOUSTIC  REACTION  WHEEL  for  illustrating  Acoustic  Repulsion. 

The  apparatus  consists  of  four  glass  resonators  fixed  upon  arms  and  centered  to  pivot  on  a  stand. 

In  use,  the  repulsion  is  so  strong  as  to  produce  uniform  rotation. 

Complete  as  illustrated 


9.76 


198 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


65-70  VIBRATION  APPARATUS  for  showing  that  sound  propagates  rarefactions  and  condensations  in  the 
surrounding  media. 

This  apparatus  consists,  as  illustrated,  of  two  circular  discs  over  one  face  of  Which  is  attached  a  plate. 
Suspended  so  as  to  rest  against  the  plate  of  one  is  a  small  ball  which  is  used  as  an  indicator  of  the 
sound  wave.  If  now  the  plate  of  the  second  is  struck  a  sharp  blow  by  means  of  the  small  hammer, 
vibrations  set  up  will  be  communicated  in  waves  to  the  first,  causing  the  small  ball  to  dance. 

This  is  a  very  striking  experiment  and  can  be  used  to  advantage  in  wave  study . 


$8.25 


66-76  VIBRATION  OF  ROD  APPARATUS  for  illustrating  the  vibration  of  a  sounding  rod. 

The  apparatus  consists  of  a  centrally  clamped  brass  rod,  one  end  of  which  is  stroked  by  resinous  cloth 
or  set  in  vibration  by  other  means.  Suspended  to  an  upright  frame  in  bi-filar  suspension  is  a  light 
sphere  which  is  adjusted  so  as  to  rest  against  one  of  the  free  ends  of  the  rod.  Any  vibration,  there¬ 
fore,  set  up  in  the  rod  is  communicated  to  the  ball,  causing  it  to  rebound  from  the  end  of  the  rod. 

Apparatus  complete  as  illustrated,  without  Basic  Clamp .  2.20 


65-80  TREVELYAN’S  ROCKER  for  illustrating  that  musical  vibrations  are  maintained  by  communication 
of  heat. 

The  apparatus  consists  of  a  brass  rod  with  a  V-groove  milled  lengthwise.  To  this  rod  is  fastened  a 
metal  handle  with  ball  end.  When  this  bar  is  heated  at  some  point  below  the  melting  point  of  lead 
and  placed  so  that  the  edges  of  the  V-groove  rest  on  the  lead  casting  as  illustrated,  the  bar  begins 
to  rock,  emitting  a  harsh  note.  This  note  may  be  made  to  rise  in  pitch  by  slightly  pressing  on 
the  bar. 

Trevelyan’s  Rocker  with  Lead  Rest .  2.00 

65-115  TYNDALL’S  TUBE  for  illustrating  the  transmission  of  sound  in  air  by  wave  motion. 

This  apparatus  consists  of  a  thin  metal  tube  built  in  sections  to  three  meters  in  length,  the  end  sec¬ 
tion  terminating  cone-shaped.  In  use  this  tube  is  mounted  on  a  simple  wooden  support.  If  a 
lighted  candle  is  placed  in  front  of  the  conical  orifice,  and  a  sharp  sound  such  as  that  emitted  by 
the  clapping  together  of  two  sticks  is  made  at  the  other  orifice,  the  wave  motion  set  up  by  the 
sound  will  be  transmitted  throughout  the  whole  length  of  the  tube,  causing  such  a  disturbance  at 
the  conical  orifice  as  to  put  out  the  candle  flame .  2.96 


21-280  CROVA’S  DISC  AND  SHIELD  for  illustrating  the  compressions  and  rarefactions  caused  among  air 

particles  by  a  sound  wave.  See  Section  21 .  2.46 


WAVE  MOTION  APPARATUS.  SECTION  26. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


199 


VELOCITY  OF  SOUND 

KUNDT’S  APPARATUS 


inri'T. 

prrrmTrrnTnWnT 

TWTTTTT' 

—x 

.W.uuti.UULLuUUUli.1. 

uUUUWj.UI.iL 

l.i.l.i.UW.i.l.iXifl.iil*iiltiil,ul*iil,i<LhW.,.U 

No.  66-20 


No.  66-30 


66-20  KUNDT’S  APPARATUS  for  demonstrating  vibrations  in  a  tube  closed  at  both  ends;  also  for  measur¬ 
ing  the  velocity  of  sound  in  air. 

The  apparatus  consists  of  a  resonance  tube,  110  centimeters  in  length,  closed  at  one  end  by  a  tight 
piston  and  near  the  other  by  a  loose-fitting  piston  at  the  end  of  a  brass  rod.  This  brass  rod,  in  use, 
is  firmly  clamped  in  a  vise.  The  tight-fitting  piston  is  adjustable  within  the  tube  by  means  of  a 
rod.  The  whole  is  compactly  mounted  on  a  neat  support. 

Complete  as  illustrated . 

66-30  KUNDT’S  APPARATUS,  with  fittings  for  the  introduction  of  various  gases  for  the  measurement  of 
the  velocity  of  sound  in  different  gases . 


MISCELLANEOUS  SUPPLIES 


No.  67-20 


67-10  PIANO  WIRE,  best  quality  imported,  wound  in  coils,  each  weighing  approximately  \i  pound. 

abed 
Diameter,  inch  .  .  .028  .022  .0178  .014 

Per  Coil  ....  $0.40  .46  .46  .66 

67-20  DOUBLE-BASS  BOW  for  setting  sounding  bodies  in  vibration. 

This  Bow  is  substantially  constructed  with  a  heavy  wooden  frame.  Length  27  inches  .  .  . 


$3.65 

8.60 


$1.36 


57-25  RESIN  for  use  on  bows  and  rods.  Best  quality  French  resin.  Per  cake,  in  cardboard  box  ...  . 


.06 


200  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


HEAT 


GENERAL  APPLIANCES  FOR  HEAT  EXPERIMENTS 

BUNSEN  BURNERS 


Our  selection  of  BUNSEN  BURNERS  from  the  many  designs  on  the  market,  has  been  based 
upon  greatest  laboratory  utility.  Thus,  there  will  be  found  in  this  list  only  burners  which  have 
given  entire  satisfaction  and  which  have  shown,  from  experience,  that  they  are  well  worthy  a  place 
in  this  edition  of  our  catalogue.  Each  burner  is  carefully  constructed  and  rigidly  tested.  The  fin¬ 
ish  is  durable,  and  designed  to  withstand  rough  usage  and  the  corrosive  action  of  chemicals  in  the 
chemical  laboratories.  We  have  given  a  considerable  latitude  for  choice,  and  there  will  be  found 
in  this  list  burners  to  meet  every  need. 


No.  60-10 


No.  60-12 


No.  60-17 


No.  60-20 


60-10 

60-12 

60-17 

60-20 

60-23 

60-25 


60-27 

60-30 

60-35 

60-38 


NORMAL  BUNSEN  BURNER  for  gasoline  or  illuminating  gas,  with  both  gas  and  air  regulation  .  . 

HARVARD  BUNSEN  BURNER,  with  regulation  for  both  gas  and  air;  tube  with  threaded  top  for 
screwing  on  of  star  for  holding  a  chimney,  a  fine  adjustment  support . 

PILOT  LIGHT  BUNSEN  BURNER  for  gas.  Screw  regulation  for  pilot,  stop-cock  for  shut-off,  air 
regulator.  Excellent  where  intermittent  flame  is  required.  Tube  34  inch  in  diameter . 


SCHOOL  BUNSEN  BURNER,  a  serviceable  gas  burner  with  air 


regulation;  diameter  of  tube  Y  inch . $0.25 

CENTRAL  DRAFT  BURNER  with  air  regulation  .  .20 

BURNER  WING  TOP  for  producing  a  hot,  smoky,  wide  flame, 

advisable  in  bending  glass  tubing  .  .16 


No.  60-27 


No.  60-30 


No.  60-36 


$1.00 


.76 


2.25 


LOW  FORM  BUNSEN  BURNER,  upward  curved  tube,  air  regulation,  height  3  inches,  diameter 


of  tube  A  inch . $0.60 

GILLEY  LOW  FORM  BUNSEN  BURNER,  as  regularly  used  with  our  Standard  Hypsometer  No. 

60-360  .  40 

ACETYLENE  GAS  BUNSEN  BURNER,  operating  efficiently,  giving  an  intense  flame.  Diameter  of 

tube  &  inch .  1.26 

ANTIMONY  RUBBER  TUBING  for  burner  connections.  This  is  the  best  quality  antimony  tubing, 
made  for  the  past  seventeen  years  from  our  own  formula. 

a  b  c: 

Inside  diameter,  inch  .  .  A  A  % 


Per  Foot  . $0.08  .12  .17 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


201 


MISCELLANEOUS  BURNERS 
BLAST  LAMPS 


No.  60-40  No.  60-46 


60-40  SEMI-BLAST  WYNNE  BURNER,  supplying  either  a  very  hot  Bunsen  flame  or  a  semi-blast,  —  in 
some  respects  preferable  to  the  ordinary  blast  flame. 

This  burner,  substantially  constructed  of  brass  and  iron,  has  regulations  for  both  gas  and  air.  Perfect 
combustion  is  insured.  Air  adjustment  is  secured  by  regulation  of  height  of  tube,  gas  adjustment 
by  a  screw.  Possibility  of  adjustment  of  flame  to  any  position  is  also  a  highly  appreciated  feature 


of  this  burner . . $1.60 

60-46  — — ,  similar  to  above,  but  adjustment  for  flame  direction  is  limited  . .  .90 


Note.  —  The  general  form  of  this  burner  has  been  copied  by  other  houses,  who  are  making  it  of 
much  lighter  material,  the  adjustments  of  cheaper  construction  and  with  no  apparent  attempt  to 
reproduce  the  form  of  the  inner  gas  chamber  which  has  made  this  burner  so  efficient. 


No.  60-76 


No.  60-100 


No.  60-110 


60-76  SOLID  BUNSEN  FLAME  STOVE.  The  advantage  of  this 
burner  is  a  broad  flame  of  uniform  temperature.  It  is 
especially  desirable  for  heating  water  in  quantities;  also  for 

rapid  heating  of  No.  60-366  Hypsometer . 

60-80  INSTANTANEOUS  HOT  WATER  HEATER.  This  ap¬ 
paratus  consists  of  a  coiled  copper  tube  enclosed  in  a 
Russia  iron  case.  Cold  water  enters  at  one  end  of  tube; 
hot  water  is  delivered  at  the  other  end,  —  instantaneous  in 
action.  Illustration  pictures  apparatus  complete  with 
No.  60-80  above  stove. 

Complete  with  Burner . 

60-81  INSTANTANEOUS  HOT  WATER  HEATER  without  Burner . 

60-100  POLISHED  COPPER  ALCOHOL  BURNER,  capacity  two  ounces. 

This  is  a  small,  highly  appreciated  burner  giving  a  very  hot  flame. 

With  ground-on  cap,  wick,  and  wick-holder . 

60-110  ALCOHOL  BURNER,  glass,  capacity  8  ounces. 

Complete  with  ground-on  cap,  wick,  and  wick-holder . 


$2.90 


9.60 

6.60 


.76 


.38 


202 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


No.  60-160  No.  60-276  No.  60-300 


60-120 

60-121 

60-136 

60-160 

60-160 


60-276 


60-300 


HOT-BLAST  ALCOHOL  STOVE.  This  is  a  compact  stove  weighing  only  5  ounces.  Its  efficiency 
is  remarkable.  In  actual  tests  water  has  been  heated  to  boiling  point  from  0  degree  Centigrade 
in  \2l/v  minutes. 

We  have  no  hesitancy  in  recommending  this  stove  for  general  use  in  laboratories  not  connected  with 


gas. 

Complete  as  illustrated,  with  tripod  support . $  0.26 

- ,  same  as  above,  without  tripod  support .  -18 


GASOLENE  BURNER.  This  burner  meets  all  the  uses  of  a  Bunsen  burner.  It  is  practically 
automatic  in  its  action,  generating  its  own  gas.  Air  pressure  is  obtained  by  small  force-pump 
contained  in  the  handle.  Flame  is  adjustable  from  very  small  height  to  5  or  6  inches,  and  will 
burn  for  IY  hours  at  full  blast  from  one  filling  of  the  reservoir,  which  holds  about  Yi  pint  of  gaso¬ 


lene  and  with  one  pumping  of  air  pressure .  3.66 

BUNSEN  BLAST  LAMP,  stable  and  durable  in  construction,  capable  of  the  most  exacting  service. 

Will  produce  the  maximum  intensity  of  heat  with  the  minimum  consumption  of  gas.  Both  air 
and  gas  pipes  supplied  with  stop-cock .  3.60 


DOUBLE  CONCENTRIC  BUNSEN  BLAST  LAMP  for  illuminating  gas  only. 

This  type  of  lamp  has  an  inner  air  jet  and  an  inner  tube  which  may  be  used  either  for  air  or  gas,  and 
an  external  gas  tube.  The  gas  and  air  are  changed  automatically  from  the  larger  to  the  smaller 
tube  by  a  slight  movement  of  the  lever  at  the  back,  the  same  movement  also  adjusting  both  gas 
and  air  to  each  other  for  each  tube.  This  combination  of  practically  two  blowpipes  gives  a  great 
range  of  power  from  a  small-pointed  jet  to  a  brisk  flame,  using  approximately  35  feet  of  gas  per 


hour  . 10.00 

FOOT  BLOWER  for  Blast  Lamp,  Blowpipe,  and  similar  work. 

This  is  a  substantially  constructed  blower  of  the  latest  pattern,  with  iron  legs,  producing  a  steady, 
powerful  blast.  Diameter  of  air  reservoir,  9  inches;  blast  pressure  per  inch,  \Yi  pounds;  cubic 

feet  of  air  per  hour,  330  .  8.76 

HAND  BELLOWS.  This  is  a  simple  inexpensive  blower,  width  7  inches,  capable  of  efficient  ser¬ 
vice  where  a  not  too  powerful  blast  is  required .  1.00 


* 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


203 


HYPSOMETERS 


No.  60-350  No.  60-365 


60-350 


60-30 

60-100 

60-366 


60-390 


GILLEY  STEAM  BOILER  or  HYPSOMETER  for  general  use  in  heat,  in  generation  of  steam,  in 
determining  the  boiling  point  of  a  thermometer,  or  for  use  where  steam  is  required  for  the  proper 
conduct  of  an  experiment. 

The  apparatus  proper  consists  of  a  carefully  constructed  copper  boiler  mounted  on  three  legs.  This 
boiler  is  constructed  of  best  quality  of  material,  all  joints  being  sealed  in  a  manner  to  obviate  the 
danger  of  destruction  due  to  careless  overheating.  Entering  the  sides  of  this  boiler  are  three 
tubes,  two  of  which  are  connected  by  rubber  and  glass  tubing  for  showing  the  water  level,  the 
third  for  attachment  of  the  pressure  gauge.  The  top  of  this  boiler  is  provided  with  a  screw  to 
which  may  be  attached  the  screw  cap  when  it  is  desired  to  use  the  boiler  merely  as  a  steam  generator. 
This  screw  must  be  replaced,  however,  by  a  thermometer  tube  in  using  the  apparatus  in  determining 
or  in  testing  the  boiling  point  of  a  thermometer.  In  specific  heat  experiments,  this  tube  is  replaced 
by  the  dipper  in  which  the  solid  is  heated. 

The  apparatus  is  furnished  complete  as  illustrated  without  Pressure  Gauge  or  Burner,  but  including 
the  Steam  Boiler,  Screw  Cap,  Thermometer  Tube,  Dipper,  and  Water  Gauge. 

This  form  of  Hypsometer  is  recommended  for  its  compactness,  stability,  and  rapidity  of  heating 
and  ease  with  which  thermometer  readings  may  be  made. 

The  tall  form  of  apparatus  brings  the  reading  portion  of  the  thermometer  scale  so  high  that  many 
students  are  not  able  to  make  accurate  readings  without  the  use  of  a  stool  or  some  other  means  of 
bringing  the  eye  to  the  right  position.  The  errors  of  parallax,  almost  unavoidable  in  the  use  of  the 


tall  form,  are  a  serious  drawback  to  its  use . $2.75 

GILLEY  LOW  FORM  BUNSEN  BURNER,  as  illustrated  in  No.  60-360  above . 40 

POLISHED  COPPER  ALCOHOL  BURNER,  capacity  2  ounces,  giving  a  very  hot  flame.  Advised 

for  use  with  No.  60-360  when  laboratory  is  not  equipped  with  gas .  .76 

STEAM  BOILER  or  HYPSOMETER,  as  designed  by  G.  M.  Turner. 


This  form  of  Hypsometer  has  received  the  same  careful  attention  in  design  and  details  of  structure 
as  our  No.  60-350.  Its  design  was  first  suggested  to  fill  the  demand  for  a  hypsometer  the  steam 
boiler  of  which  could  be  detached  from  the  tripod  support  and  which  could  make  use  of  the  ordi¬ 
nary  type  of  Bunsen  burner.  As  may  be  noted  from  the  illustration,  our  design  fulfils  these  re¬ 
quirements.  This  form  has  the  further  advantage  over  our  No.  60-360  in  that  it  may  be  used 
on  a  stove  similar  to  our  Nos.  60-76  and  60-120,  the  stoves  in  these  cases  answering  the  purpose 


of  the  tripod  support. 

Complete  as  illustrated,  with  tripod  support,  steam  boiler,  screw  cap,  dipper  and  thermometer  tube  2.95 
IMPROVED  FORM  PRESSURE  GAUGE,  especially  adapted  for  use  with  Hypsometer  No.  60-360, 

on  which  instrument  it  will  be  found  illustrated .  .11 


204 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  60—430 


No.  61-10 


No.  61-11 


60-326  POLISHED  COPPER  BEAKER,  of  heavy  polished  copper,  of  extreme  utility  in  a  great  number  of 
experiments  requiring  the  use  of  an  indestructible  utensil  for  boiler,  etc.  Capacity  500  cubic 


centimeters  . . $0.90 

60-330  POLISHED  ALUMINUM  BEAKER,  similar  to  above,  500  cubic  centimeters  capacity .  1.00 

60-400  WATER  TRAP,  IMPROVED  DESIGN,  essential  in  determining  the  latent  heat  of  steam  by  pre¬ 
venting  any  condensed  steam  passing  into  the  calorimeter. 

Our  design  has  been  improved  by  the  short  curved  end  which  entirely  obviates  any  danger  of  con¬ 
densed  steam  passing  through  into  the  calorimeter .  .36 

60—406  H-K  STEAM  TRAP,  consisting  of  bottle  with  glass  tubes  and  stopper  arranged  to  catch  any  con¬ 
densed  steam  as  it  passes  through  the  bottle .  .46 

60-430  GALVANIZED  IRON  ICE  TRAY,  designed  especially  for  cooling  dry  air  enclosed  in  Charles  Law 

Tube.  With  tubulature  as  illustrated .  .76 

60-435  CANVAS  ICE  BAG  for  crushing  ice  into  small  fragments  for  calorimetric  determinations .  .17 

60-440  ICE  SHREDDER  and  SHAVE,  coarse  or  fine  shavings .  1.26 


RADIATION,  REFLECTION,  CONDUCTION 

CONVECTION 


61-10  CROOKE’S  RADIOMETER,  illustrating  attraction  and  repulsion  arising  from  radiation. 

This  instrument  consists  of  a  very  light  vane  constructed  of  thin  mica  discs  fastened  at  the  ends  of 
four  arms  of  aluminum  wire,  the  whole  arranged  to  turn  very  freely  about  a  vertical  axis  and  en¬ 
closed  in  a  glass  vessel  which  is  highly  exhausted.  Each  of  these  mica  discs  is  blackened  on  one 
side.  On  exposing  the  Radiometer  to  any  source  of  radiant  heat  the  vane  revolves  in  such  a  direc¬ 
tion  that  the  blackened  faces  are  always  receding. 

Mounted  on  glass  foot . $1.66 

61-11  CROOKE’S  DOUBLE  RADIOMETER,  similar  to  above,  but  with  two  bulbs,  in  each  of  which  is 
mounted  a  vane  pivoted  independently  with  its  blackened  faces  opposite  to  each  other. 

Mounted  on  glass  foot  . . . 


4.00 


No.  62-10 


62-10  THIRTEEN-INCH  UNIVERSALLY  ADJUSTABLE  TRUE  PARABOLIC  REFLECTORS,  for  dem¬ 
onstrating  Reflection  of  Sound,  Heat  and  Light  Waves. 


In  offering  for  sale  our  Improved  Reflectors  we  desire  to  emphasize  the  TRUE  PARABOLIC  SUR¬ 
FACES.  The  curves  of  these  surfaces  have  been  accurately  calculated  and  then  by  painstaking 
processes  a  chuck  has  been  turned  to  the  true  parabolic  curve.  Our  Reflectors  are  all  spun  from 
this  chuck.  The  reflecting  surface  is  then  highly  polished  and  heavily  nickel-plated,  presenting  an 
excellent  surface  without  waves. 


The  Reflectors  are  mounted  in  a  two-part  circular  casting  in  such  a  manner  as  to  entirely  obviate 
any  danger  of  distorting  the  surfaces.  This  two-part  casting  is  brought  together  at  the  bottom, 
where  it  makes  a  swivel  junction  with  a  rod  which  telescopes  into  the  supporting  base. 

The  Holders  and  Attachments  are  all  of  special  design  which  allows  of  both  coarse  and  fine  adjust¬ 
ments.  We,  therefore,  secure  a  tilting  movement  for  the  Reflectors,  an  adjustment  for  proper 
height,  and  universal  movements  for  each  attachment. 

In  demonstrating  reflection  of  heat  waves  either  a  candle  or  a  heated  metal  ball  may  be  used  in  one 
of  the  Carriers  at  the  focus  of  one  reflector;  if  now  a  piece  of  phosphorus  be  placed  at  the  focus  of 
the  other  reflector  in  its  Carrier,  the  heat  waves  brought  to  a  focus  will  cause  the  phosphorus  to 
burn. 

The  finish  of  this  instrument  is  fully  in  keeping  with  the  design.  The  outer  surfaces  of  the  reflectors 
are  dull  oxidized,  the  H-Base  japan,  and  all  brass  parts  polished  and  nickel-plated. 

Thirteen-inch  Universally  Adjustable  True  Parabolic  Reflectors  complete  as  illustrated  with  Attach¬ 
ments  . .  .Per  Pair  $17.60 


62-16  THIRTEEN-INCH  UNIVERSALLY  ADJUSTABLE  TRUE  PARABOLIC  REFLECTORS,  same  as 

above,  mounted  on  stand  but  without  Attachments  or  Carriers . Per  Pair  13.60 


206 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  } 


ABSORPTION  — RADIATION  SCREENS 


No.  61-70 


No.  61-76 


No.  61-100 


61-70  ABSORPTION  SCREEN  for  the  comparative  illustration  of  the  absorptive  power  of  two  different 
substances. 

This  is  a  screen  of  polished  metal  with  ring  of  black  painted  on  face,  and  the  back  coated  with  red 
mercuric  oxide. 

If  a  source  of  radiant  energy  is  held  in  front  of  the  face,  a  ring  will  be  reproduced  in  yellow  on  a  red 
ground  on  the  back  of  the  screen.  As  the  mercuric  oxide  turns  yellow  at  150  degrees  Centigrade, 
it  may  be  concluded  that  a  black  surface  has  more  absorptive  power  than  a  polished  surface  .  .  $2.86 

61-75  RADIATION  SCREENS  for  comparative  illustration  of  the  absorptive  power  of  two  different 
substances. 

This  apparatus  consists  of  a  pair  of  screens,  10  inches  square,  one  of  polished  metal,  the  other  of  metal 
with  the  face  blackened,  each  screen  with  small  ledges  at  the  back  for  pieces  of  phosphorus. 

When  placed  facing  source  of  radiant  energy,  it  will  be  noted  that  the  action  upon  the  phosphorus  is 
immediate  in  the  case  of  the  blackened  screen,  whereas  the  energy  is  deflected  on  the  polished 
screen,  demonstrating  the  absorptive  power  of  a  blackened  surface  and  the  reflecting  power  of  the 
polished  surface . Per  pair  4.26 

61-100  LESLIE’S  CUBE  for  the  comparative  illustration  of  the  emissive  powers  of  different  substances. 

This  is  a  hollow  metal  cube,  2^  inches  on  an  edge,  one  face  polished,  the  other  three  coated  with  dif¬ 
ferent  substances  which  have  different  emissive  powers.  A  tubulature  is  provided  at  top  for  intro¬ 
duction  of  hot  water  and  then,  if  desired,  for  a  thermometer. 

When  these  surfaces  are  allowed  to  radiate  in  succession  against  the  face  of  a  thermopile  or  other 
delicate  radiometer,  it  will  be  noted  that  the  indications  vary,  showing  the  polished  metal  a  very 
poor  radiator,  the  other  substances  varying  in  emissive  powers. 

Leslie’s  Cube  only,  without  Thermopile  and  without  Stand,  with  three-sided  protective  case  .  .  .  1.36 

61-106  - ,  with  four  polished  faces,  each  of  different  metals . $1.65 

THERMOPILES.  For  illustration  and  description  see  Section  64. 

64-15  DIFFERENTIAL  THERMOMETER,  frequently  desired  in  con¬ 
nection  with  Leslie’s  Cube.  For  illustration  and  description  see 
Section  64  . 7.50 

01-135  COOLING  CUP,  after  Turner  and  Hersey  (Experiment  No.  H100), 
for  comparing  the  rate  of  cooling  of  different  substances. 

The  apparatus  consists  of  two  cooling  cups,  one  nickel-plated,  the 
other  blackened,  with  two  wooden  covers  each  with  hole  for 
thermometer. 

In  use,  each  is  supported  in  the  ring  of  a  Ring  Stand  on  Wooden 
Support  Ring.  Hot  water  is  poured  into  each  and  curve  of  rate  of 
cooling  is  determined  by  the  reading  of  the  thermometers. 

Apparatus  complete,  with  two  Cups,  one  nickel-plated,  the  other 
blackened,  two  Support  Rings,  and  two  Covers . 1.65 


No.  61-135 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


207 


61-160 

61-160 

61-161 

70-50b 

61-163 

61-176 


61-178 


61-180 

61-183 

61-186 


No.  61-175  No.  61-185 


CONVECTION  OF  HEAT 

CONVECTIONAL  CURRENT  APPARATUS  for  illustrating  Convectional  Currents  in  Liquids. 

When  the  tube  is  heated  in  the  lower  part,  currents  are  set  up.  These  currents  will  be  readily  noted 
by  introduction  of  a  few  grains  of  cork  dust  or  addition  of  some  aniline  dye . $1.15 

CONVECTIONAL  CURRENT  APPARATUS  for  illustrating  Convectional  Currents  in  Air. 

By  placing  a  burning  candle  in  the  box  under  one  of  the  chimneys,  convectional  currents  are  set  up, 
as  may  be  demonstrated  by  use  of  burning  Touch  Paper  or  other  smoke  producers,  at  the  open 
end  of  the  other  chimney.  Without  candle .  1.90 


CHIMNEYS,  straight  form . Each  .15 

CANDLES,  twelves  (12  to  the  pound) . Per  dozen  .20 

TOUCH  PAPER . Sheet  .10 


CONDUCTION  OF  HEAT 

HARCOURT  COMBINATION  VERTICAL  CONDUCTOMETER  for  illustrating  relative  con¬ 
ductivities  of  different  solids. 

This  apparatus  consists  of  a  cored  casting  into  which  steam  may  be  led  from  some  steam  generator. 

(See  Hypsometers  Nos.  60-360  and  60-366.)  The  top  of  this  casting  is  provided  with  tubulatures 
into  which  are  placed  the  stoppers  holding  the  different  metal  rods.  Each  rod  is  provided  with 
cavities  in  the  upper  end  for  phosphorus  and  in  addition  is  coated  with  a  heat  indicating  paint  .  $3.93 

HEXAGONAL  COMBINATION  CONDUCTOMETER  for  illustrating  the  conductivity  of  dif¬ 
ferent  metals. 

This  conductometer  consists  of  a  hexagonal  casting,  into  five  faces  of  which  are  threaded  five  rods  of 
different  material;  into  the  sixth  face  is  threaded  a  brass  rod  terminating  in  a  handle.  On  each 
rod  at  equal  distances  from  the  faces  are  cavities  for  phosphorus.  Each  rod  in  addition  is  coated 


with  a  heat  indicating  paint .  1.60 

PRIMARY  CONDUCTOMETER  for  illustrating  conductivity  of  metals. 

Four  rods  of  different  metals  fastened  to  a  wooden  backing .  .35 

CONDUCTIVITY  RODS,  set  of  three,  8  centimeters  long .  .30 

COMPOUND  ROD  for  comparative  conductivity  illustration. 

This  consists  of  a  rod,  5  inches  by  x/i  inch  diameter,  part  of  which  is  wood,  part  brass.  When  heated 

at  middle  and  held  in  hand,  the  relative  conductivity  may  be  readily  noted .  35 


. 

208  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  61-195 


No.  61-200 


No.  61-210 


No.  61-205 


61-195  CONDUCTIVITY  OF  WATER  APPARATUS,  after  Millikan  and  Gale,  Figure  198.  Without  stand 

and  dish . $  0.65 

61-200  DEWAR  BULB,  illustrating  the  practically  non-conductivity  of  a  vacuum,  designed  for  transport¬ 
ing  liquid  air. 

This  consists  of  a  double-walled  glass  vessel,  the  chamber  between  walls  being  exhausted.  Capacity 

500  c.c .  3.90 

61-205  UNEXHAUSTED  DEWAR  BEAKER  for  study  of  heat  insulating  qualities  of  a  vacuum  chamber. 

This  apparatus  consists  of  a  double-walled  vessel  with  tube  entering  inner  chamber  for  purpose  of 

exhausting  same .  3.25 

61-210  STEEL  ENCASED  SOLID  ALUMINUM-LINED  FIRELESS  COOKER.  In  Manual  Training 
Schools,  Vocational  Schools,  and  schools  giving  courses  for  young  women,  the  Fireless  Cooker 
has  become  a  prominent  and  important  feature. 

It  should  be  the  design  of  every  course  in  Physics  to  study  the  scientific  aspects  of  the  Fireless  Cooker 
in  its  relation  to  questions  of  conduction,  convection,  and  temperatures,  and  time  required  to 
produce  the  fundamental  chemical  changes  occurring  in  the  process  of  cooking. 

This  cooker  is  of  the  very  best  make,  worked  out  upon  a  scientific  basis.  The  radiator  is  of  soap¬ 
stone.  The  cooking  compartments  are  of  solid,  seamless  aluminum,  provided  with  ample  heat 
insulation.  The  case  is  of  planished  steel,  provided  with  legs  and  castors.  Size  2034  inches  high, 

1634  inches  wide  and  1634  inches  long. 

Furnished  complete  with  one  12-quart  aluminum  kettle,  two  heat  radiators,  radiator  thermometer, 
one  radiator  rack,  one  pair  individual  pastry  and  cake  shelves,  radiator  hook  and  book  of  di¬ 
rections  . 16.00 

Note.  —  We  are  prepared  to  furnish  larger  sizes  than  listed  above.  Prices  on  application. 

61-215  DAVY’S  SAFETY  LAMP,  illustrating  the  high  conductivity  of  metal  gauze.  Valuable  in  mines 
against  “fire  damp,’’  in  that  although  an  explosive  mixture  may  burn  within  the  gauze,  the  flame 
cannot  pass  through  it  to  the  gas  outside . .  2.60 

61-220  LIQUID  CONDUCTION  TUBE,  illustrating  the  slight  conduction  qualities  of  water.  W’ater  may 

be  boiled  in  upper  part  while  ice  remains  unmelted  at  lower  end .  .15 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


209 


4 


62-10 


62-11 

62-16 


62-16 


PAPIN  DIGESTER,  illustrating  the  rise  in  boiling  point  by  increase 
in  pressure. 

This  is  a  strongly  constructed  brass  boiler  about  5  inches  high  by 
inches  average  diameter.  With  gasket  and  heavy  metal  cap, 
which  may  be  rigidly  clamped  to  boiler.  This  cap  is  provided 
with  a  hole  for  thermometer  and  also  with  a  safety  valve. 

Complete  as  illustrated  with  Safety  Valve  and  Weight,  Tripod  Sup¬ 
port,  and  Thermometer . $14.00 

- ,  similar  to  above,  but  with  addition  of  Pressure  Gauge  .  .  .  17.50 

BOILING  POINT  OF  ALCOHOL  TUBE,  after  Millikan  &  Gale’s 
“A  Laboratory  Course  in  Physics,”  Exercise  23,  for  determining 
the  boiling  point  of  alcohol  by  finding  the  point  at  which  its 
saturated  vapor  pressure  is  equal  to  the  atmospheric  pressure. 

This  is  a  simple  form  of  U-Tube,  closed  at  one  end.  In  use  it  is  par¬ 
tially  filled  with  mercury  and  alcohol  carefully  worked  around 
into  the  closed  arm  from  which  the  air  is  altogether  driven.  The 
alcohol  is  vaporized  by  immersion  in  a  hot  bath.  When  vapor 
pressure  equals  atmospheric  pressure,  the  mercury  will  be  at 
the  same  height  in  both  arms.  The  temperature  of  the  water 
bath  at  this  point  will  be  the  boiling  point  of  alcohol. 

Tube  oWy,  unfilled . 

BEVELED  GLASS  TUBE,  20  cm.,  after  Turner  and 

Hersey  Exp.  H012 . $0.12 

VAPOR  PRESSURE  TUBE,  for  determining  vapor 
pressure  and  boiling  point  of  a  liquid. 

This  apparatus  consists  of  a  U-Tube,  one  branch  of 
which  is  provided  with  stop-cock,  an  indispensable 
feature  for  excluding  the  air  in  the  closed  arm  and 
for  the  introduction  of  the  liquid;  also  for  the 
proper  cleaning  of  the  tube  after  use  ...  1.45 


.30 


\J) 


KNOTT  BOSTON 


No.  62-20 


No.  62-62 


of 


VAPOR  TENSION  APPARATUS,  for  direct  comparison  and  measurement 
the  vapor  tensions  of  different  liquids. 

The  apparatus  consists  of  four  heavy-walled  glass  tubes  connected  through  a 
stop-cock  at  the  top  to  a  small  reservoir.  These  four  tubes  are  held  by  a 
special  clamp  to  a  metal  upright  supported  on  our  H-Base.  A  second  clamp 
trough  casting  is  provided  for  mercury  into  which  the  open  ends  of  the  tubes 
dip.  Each  tube  has  an  individual  trough  of  its  own,  thus  avoiding  expense  of 
an  unnecessary  amount  of  mercury. 

Complete  as  illustrated  with  four  tubes . 


$8.75 


VAPOR  TENSION  TUBES,  as  used  in  above 


Each  1.50 


62-62 


VAPOR  TENSION  APPARATUS,  similar  to  above,  but  tubes  not  provided 
.with  stop-cocks.  Each  tube  is  heavy  walled  with  closed  end.  Complete 
with  four  tubes,  supporting  upright,  clamp,  and  mercury  reservoir  ....  4.45 

VAPOR  TENSION  TUBES,  as  used  in  above . Each  .28 

VAPOR  TENSION  TUBE  with  CAPILLARY  OF  KNOWN  VOLUME.  This 
tube  may  be  adjustably  mounted  in  place  of  air  thermometer  bulbs  as  illustra¬ 
ted  under  No.  64-55  (see  Section  64).  At  the  upper  part  of  the  tube  there 
are  two  stop  cocks  between  which  is  a  capillary  of  known  volume.  Most 
accurate  determinations  of  vapor  tension  are  possible  with  this  tube.  Each  3.00 


210 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


VAPORIZATION,  BOILING,  DISTILLING, 

FREEZING,  STILLS 


No.  62-70 


62-70  STILL,  for  distillation  of  water  or  spirits. 

This  apparatus  consists  of  a  heavy  tin-lined  copper  boiler  with  movable  head,  connected  with  the 
pure  block  tin  condensing  worm  enclosed  in  a  zinc  vessel,  provided  with  proper  inlets  and  outlets. 
Complete  as  illustrated. 

a  b  c  d  e 

Capacity,  gallons  .  .  yi  1  2  3  5 

Each . $10.60  12.40  14.60  19.75  26.60 


No.  62-80 


62-80  ACME  WATER  STILL.  This  still  is  a  perfect  apparatus  for  the  production  of  pure  water  by  distil¬ 
lation.  The  distillate  is  cold,  and  aerated  if  desired.  The  apparatus  is  of  first-class  workmanship 
throughout  and  is  made  of  copper  and  brass,  tin-lined  and  nickel-plated.  The  gas  and  water  connec¬ 
tions  are  extremely  simple.  The  Acme  Water  Still  runs  automatically  and  there  is  nothing  to  get 
out  of  order.  It  is  started  and  stopped  in  a  moment.  The  “Acme”  is  comparatively  the  fastest 
and  most  economical  Water  Still,  as  it  produces  a  gallon  of  distilled  water  in  about  hours,  at 
a  cost  of  about  cents  per  gallon.  It  is  the  most  durable  still,  and  will  practically  last  a  life¬ 
time,  as  the  mineral  and  other  matter  that  remains  in  the  retort  is  drained  off  through  the  flushing 
outlet,  this  being  done  in  a  moment  without  any  trouble  and  without  displacing  the  still  or  taking 
it  to  pieces.  The  combustion  of  gas  with  our  special  burner  is  perfect  and  all  the  heat  is  fully 
utilized.  Wall  space  required  4  X  12  inches,  extreme  width  8  inches,  projection  14  inches. 

Still  as  illustrated  with  burner  for  coal  or  water  gas,  natural  gas,  or  acetylene . 


$24.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


No.  62-120 


No.  62-140 


No.  62-160 


62-90  WOODEN  HEAT  SHIELD,  for  use  as  insulator  of  heat  when  it  is  desired 
to  shield  part  of  an  experiment  from  heat  rays  emitted  from  another 
part,  especially  when  in  calorimetry  it  is  desired  to  use  a  steam  boiler. 

The  shield  consists  of  a  board,  mounted  upright  on  a  base.  This  board  is 
provided  with  hole  for  passage  of  delivery  tube  for  the  steam  generated 
in  the  boiler . 

62-120  LIEBIG’S  METAL  CONDENSER,  for  the  distillation  of  liquids. 

This  condenser  is  made  of  brass  and  highly  polished.  Length  30  inches; 
diameter  1  7/8  inches.  This  form  prevents  breakage . 

62-125  LIEBIG’S  CONDENSER,  entirely  of  glass,  condensing  tube  fitted  to  jacket 
by  rubber  connection.  Length  12  inches  . 

62-126  —  — ,  same  as  above,  but  24  inches  long . 

HARCOURT  ECONOMY  MERCURY  STILL.  See  index. 

62-140  FRANKLIN’S  PALM  or  PULSE  GLASS,  for  illustrating  influence  of  pres¬ 


sure  on  boiling. 

This  glass  consists  of  two  bulbs  joined  by  a  tube  which  is  filled  with  a  colored  liquid  and  from  which 
air  has  been  expelled  as  completely  as  possible  by  boiling  the  liquid  before  sealing  the  tube.  There 
is  then  in  the  glass  a  pressure  due  to  the  elastic  force  of  the  aqueous  vapor  which  at  ordinary  tem¬ 
perature  is  very  small.  If,  now,  one  of  the  bulbs  be  held  in  the  hand,  the  heat  is  sufficient  to 
produce  a  pressure  which  drives  the  liquid  into  the  other  bulb  and  causes  it  to  boil  violently, 
the  hand  feeling  also  a  sensation  of  cold . 


$0.46 

2.75 


.85 

1.60 


.35 


62-160  WOLLASTON  CRYOPHORUS,  illustrating  freezing  by  evaporation. 

In  use,  the  water  is  introduced  into  the  bulb  on  the  bent  neck  and  the  other  bulb  is  placed  in  a  freez¬ 
ing  mixture.  The  vapor  then  is  condensed  in  the  tube,  causing  the  water  in  the  bulb  to  evaporate 
rapidly'  in  order  to  yield  more  vapor.  This  rapid  evaporation  causes  the  water  in  the  bulb  to 
freeze.  Without  jar  .  1.40 


62-166  CARRE’S  FREEZING  APPARATUS  for  connecting  to  an  Air  Pump,  illustrating  freezing  of  water 
by  its  own  rapid  evaporation,  at  the  same  time  causing  ether  to  boil. 

A  few  strokes  of  the  piston  of  the  Air  Pump  cause  the  water  in  the  flask  to  evaporate  rapidly.  The 
vapor  is  absorbed  at  once  by  the  sulphuric  acid,  causing  more  rapid  evaporation  of  the  water,  at 
the  same  time  increasing  its  own  temperature  to  such  an  extent  as  to  cause  the  ether  to  boil,  and  if 
the  tube  containing  the  ether  has  been  lightly  stoppered,  causing  the  cork  to  fly  out .  2.16 


212 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


<5= 


No.  62-160 


No.  62-200 


No.  62-240 


No.  43-310 


62-160  SULPHURIC  ACID  CRYOPHORUS,  for  freezing  water  by  its  own  rapid  evaporation. 

When  the  top  bulb  has  been  half  filled  with  water  and  the  middle  bulb  filled  with  strong  sulphuric 
acid,  the  vessel  should  be  clamped  in  a  position  as  shown  in  the  illustration.  The  water  is  then 
heated  until  about  1/3  has  been  driven  off  in  steam.  The  lower  neck  is  then  tightly  corked  by 
means  of  a  stopper  plug  covered  with  a  piece  of  india  rubber  tubing,  and  the  burner  is  removed. 

The  water  is  then  cooled  by  immersing  in  a  cold  bath.  When  sufficiently  cooled,  the  apparatus  is 
turned  round  a  number  of  times,  in  such  a  way  that  the  acid  can  run  in  and  out  of  the  middle  bulb 
while  the  water  is  not  allowed  to  leave  the  top  bulb.  The  heat  generated  by  the  absorption  of 
water  vapor  drives  out  any  air  which  may  be  dissolved  in  the  acid.  The  stopper  is  removed  and 
the  boiling  is  continued  as  described  above.  After  passing  the  acid  several  times  to  and  from  the 
middle  bulb,  the  water  in  the  top  bulb  will  be  found  to  solidify.  Care  must  be  taken,  however, 
throughout  the  experiment  to  prevent  any  acid  passing  over  into  the  water  bulb,  or  the  experiment 
will  not  be  a  success. 

Cryophorus  complete  as  illustrated  with  Stopper  Plug  and  Delivery  Tube .  $1.90 

43-310  FREEZING  APPARATUS,  illustrating  the  freezing  of  water  by  the  rapid  evaporization  of  ether. 

As  air  is  exhausted  from  bell  glass,  the  ether  evaporates  very  rapidly,  causing  water  in  watch  glass  to 
freeze. 

Complete  as  illustrated .  1.40 


62-200  DEW  POINT  APPARATUS,  after  Millikan,  Gale  and  Bishop,  Exp.  10A,  for  determining  the  tem¬ 
perature  at  which  water  vapor  begins  to  condense  out  of  the  atmosphere  as  the  temperature  is 
lowered^ 

•  In  use,  the  metal  tube  is  filled  two-thirds  full  with  ether.  Air  is  forced  very  gently  through  this 
ether  by  means  of  the  bulb.  This  process  facilitates  cooling,  since  it  increases  the  evaporating 
surface.  The  temperature  existing  within  the  tube  when  the  first  cloudiness  begins  to  appear 
upon  the  polished  surface  is  the  Dew  Point. 

Complete  as  illustrated .  .96 

62-226  MELTING  POINT  TUBE,  for  determining  the  melting  point  of  paraffine,  wax,  and  other  substances 
which,  when  in  solid  state,  have  a  color  but  which  turn  colorless  in  liquid  state. 

This  tube  consists  of  a  glass  tube  with  end  bent  and  drawn  to  a  point.  While  hot,  the  substance  is 
drawn  into  the  tapered  point.  It  is  then  allowed  to  cool  when  it  is  immersed  into  water,  the 
temperature  of  which  is  gradually  increased  until  the  substance  loses  color,  when  temperature  is 
noted  by  thermometer.  This  reading  will  be  the  melting  point  of  the  substance  .  ., .  .16 

62-240  CUBICAL  EXPANSION  BULB,  for  determining  the  point  of  maximum  density  of  water.  This 
apparatus  consists  of  a  bulb'  of  known  volume  with  graduated  capillary  neck. 

When  filled  with  water,  sufficient  to  fill  the  bulb  and  three  quarters  of  the  graduated  neck,  the  bulb 
is  immersed  in  water,  the  temperature  of  which  is  taken.  Freezing  mixture  is  added  to  bath  and 
continuous  readings  of  thermometer  and  graduated  neck  are  taken.  A  point  will  soon  be  reached 
where  the  reading  on  the  neck  does  not  descend  as  the  temperature  decreases  but  at  this  point 
will  begin  to  rise,  showing  that  this  is  the  point  of  maximum  density.  This  point  will  be  found 
at  about  4  degrees  Centigrade .  1.10 


X 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


213 


MEASUREMENT  OF  INTENSITY  OF  HEAT 

THERMOMETERS 


No.  63-10 


No.  63-12 


No.  63-16 


63-10  HOUSEHOLD  THERMOMETER,  8  inches  long,  heavy  metal  frame,  reading  from  -30 

degrees  to  120  degrees  Fahrenheit . . . $0.60 

63-12  HOUSEHOLD  THERMOMETER,  10  inches  long,  silvered  scale  on  hardwood  back,  read¬ 
ing  from -30  degrees  to  120  degrees  Fahrenheit . 95 


63-16  COMPARATIVE  THERMOMETER,  three  Scale,  Fahrenheit,  Centigrade,  and  Reaumur.  No.  63-20 

This  is  a  thermometer,  10  inches  long,  designed  to  give  the  student  an  instrument  which 
will  give  a  reading  in  all  three  scales,  thus  showing  direct  comparisons.  Made  of  box¬ 
wood,  piano  rubbed  finish,  all  graduations  and  letterings  distinct.  Bulb  protected  by 
metal  covering .  .80 

63-18  METALLIC  THERMOMETER,  DEMONSTRATION  FORM,  with  glass  back,  entire  mechanism 
visible.  Diameter  6  inches.  This  thermometer  will  be  of  great  pedagogic  value  in  that  it  shows 
at  a  glance  the  method  of  multiplying  the  movement  made  by  two  metals  soldered  together. 

Range  from  50  degrees  below  to  150  degrees  Fahrenheit .  $4.40 

63-20  GROUND  GLASS  UNGRADUATED  THERMOMETER,  13  inches  long,  half  its  circumference 
etched  through  its  entire  length.  In  calling  attention  to  this  thermometer,  we  request  that  it  be 
not  confused  with  those  on  the  market.  With  this  thermometer,  a  student  can  find  and  mark 
in  pencil  on  the  etched  portion  both  its  zero  and  boiling  points.  When  these  are  obtained,  it  will 
require  very  little  skill  on  his  part  to  make  a  complete  thermometer.  The  etched  portion  obviates 
the  disagreeable  features  of  rubber  bands  and  otherindicators.  Each  50  cents  ....  Per  Doz.  6.76 


214 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


CHEMICAL  THERMOMETERS 


No.  63-30  No.  63-37  No.  63-60  No.  63-60  No.  63-70 


63-26  CHEMICAL  THERMOMETER,  paper  scale,  8  inches  long,  with  scale  reading  from  -10  to  100°  Centi¬ 


grade,  enclosed  in  case . $0.76 

63-26  - ,  paper  scale,  8  inches  long,  with  scale  reading  from  0  to  220°  Fahrenheit,  enclosed  in  case  ...  .66 

63-30  CHEMICAL  THERMOMETER,  paper  scale,  13  inches  long,  with  scale  reading  from  -10  to  110° 

Centigrade,  enclosed  in  case  .  1.00 

63-32  - ,  paper  scale,  13  inches  long,  with  scale  reading  from  -10  to  210°  Centigrade,  enclosed  in 

case .  1.00 

63-36  - ,  paper  scale,  13  inches  long,  with  scale  reading  from  15  to  220°  Fahrenheit,  enclosed  in 

case . "...  1.00 

63-36  - ,  paper  scale,  13  inches  long,  with  scale  reading  from  15  to  400°  Fahrenheit,  enclosed  in 

case .  1.26 

63-37  CHEMICAL  THERMOMETER,  paper  scale,  13  inches  long,  with  double  scale  reading  from  -10  to 
110°  C.  and  with  equivalent  Fahrenheit  scale  to  220°. 

Enclosed  in  case .  1.16 


lent  Fahrenheit  scale  to  400°. 

Enclosed  in  case .  1.36 

63-60  CHEMICAL  THERMOMETER,  stem  scale,  white  enameled  back,  13  inches  long,  graduated  from 
-10  to  110°  C. 

Enclosed  in  wooden  case .  1.16 

63-62  -  — ,  stem  scale,  white  enameled  back,  13  inches  long,  graduated  from  -10  to  210°  C. 

Enclosed  in  wooden  case .  1.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


215 


63-55  CHEMICAL  THERMOMETER,  stem  scale,  white  enameled  back,  14  inches  long,  graduated  from 

-10  to  360°  Centigrade,  enclosed  in  wooden  case . $1.50 

63-67  -  — ,  stem  scale,  white  enameled  back,  14  inches  long,  graduated  from  15  to  600°  Fahrenheit,  en¬ 
closed  in  wooden  case .  1.50 

63-60  -  — ,  stem  scale,  white  enameled  back,  14  inches  long,  double  graduations,  from  -10  to  110°  Centi¬ 
grade  and  with  equivalent  Fahrenheit  scale  to  220°,  enclosed  in  wooden  case .  1.50 

63-62  -  — ,  stem  scale,  white  enameled  back,  14  inches  long,  double  graduations,  from  -10  to  210°  Centi¬ 
grade  and  with  equivalent  Fahrenheit  scale  to  400°,  enclosed  in  wooden  case .  1.75 

63-64  -  — ,  stem  scale,  white  enameled  back,  14  inches  long,  double  graduations,  from  -10  to  360°  Centi¬ 
grade,  with  equivalent  Fahrenheit  scale  to  600°,  enclosed  in  wooden  case  .  2.00 

63-70  CHEMICAL  THERMOMETER,  enclosed  milk  glass  scale,  13  inches  long,  graduated  from -10  to  110° 

Centigrade,  enclosed  in  wooden  case .  1.25 

63-72  - ,  enclosed  milk  glass  scale,  13  inches  long,  graduated  from  -10  to  250°  Centigrade,  enclosed  in 

wooden  case .  1.50 


STANDARD  THERMOMETERS 

63-80  STANDARD  CHEMICAL  THERMOMETER,  scale  engraved  on  the  stem,  white  enameled  back,  16 

inches  long,  graduated  from  0  to  100°  Centigrade  by  1/5  degrees,  enclosed  in  wooden  case  ....  $3.00 

63-86  STANDARD  CHEMICAL  THERMOMETER,  scale  engraved  on  the  stem,  white  enameled  back, 

25  inches  long,  graduated  from  0  to  100°  Centigrade  by  1/10  degrees,  enclosed  in  wooden  case  .  .  4.60 


No.  63-146 


63-125 


63-135 


STANDARD  THERMOMETERS,  Centigrade  scale,  engraved  stem,  each  with  zero  and  boiling 
points.  Set  of  four  as  follows,  enclosed  in  fine  leather  case: 

0  to  100°  X  1/10  100  to  200°  X  1/10 

200  to  300°  X  1/5  300  to  400°  X  yi 

Duty  Free  $19.80 


STANDARD  THERMOMETERS,  Centigrade  scale,  after  Allihn,  enclosed  pearl  glass  scale,  set  of 
three  about  12  X  V±  inch,  each  with  zero  and  boiling  points,  divided  to  ]/2  degrees.  Set  as  follows: 
-15  to  100°  100  to  200°  200  to  300° 

In  fine  leather  case,  Duty  Free 


13.50 


63-146  STANDARD  THERMOMETERS,  Centigrade  scale,  after  Anschuetz_,  enclosed  pearl  glass  scale, 
about  4  to  6  inches  long  by  inch  diameter.  Set  of  seven  by  1/5  degrees  as  follows: 

10  to  60°  40  to  110°  90  to  160°  150  to  220°  200  to  270°  250  to  310°  300  to  360° 

In  fine  leather  case,  Duty  Free 


14.76 


2l6 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


MISCELLANEOUS  STANDARD 
THERMOMETERS 


63-155  BECKMANN’S  NORMAL  DIFFERENTIAL  THERMOMETERS,  for  boil¬ 
ing  or  freezing  point  methods  in  molecular  weight  determinations,  etc. 


a  b 

Range,  Degrees  C.  1  5  to  6 

Divided,  degree  .  1/500  1/100 
Each,  Duty  Free  .  $9.80  6.60 


c  d 

i 

10  to  12  25  to  30 

1/50  1/20 

6.60  6.25 


e 

50  to  60 
1/10 
6.25 


63-166  CALORIMETRIC  THERMOMETER,  about  20  inches  long,  scale  engraved 
on  pearl  glass,  from  15  to  25  degrees  Centigrade  by  1/100  degree  Duty  Free 

63-170  HYPSOMETER  THERMOMETER,  scale  etched  on  stem,  length  about  14 
inches,  90  to  102°  Centigrade  by  1/10  degree,  with  zero  and  boiling  points. 

Duty  Free 

63-172  - ,  same  as  above,  95  to  102°  C.  by  1/20  degree . Duty  Free 

63-180  HIGH  TEMPERATURE  THERMOMETERS,  Centigrade  scale,  about  12  to 

14  inches  long,  in  the  following  ranges  by  single  degrees: 

0  to  130°  100  to  300°  200  to  540° 

Per  set  of  three,  in  fine  leather  case.  Duty  Free 

63-182  -  — ,  same  as  above,  but  with  certificate  of  accuracy  from  Physik-Technische 

Reichsanstalt  in  Charlottenburg . Duty  Free 

63-190  LOW  TEMPERATURE  THERMOMETER,  stem  graduation  by  single 
degrees,  from  -50  to  50°  Centigrade;  without  certificate  .  .  .  Duty  Free 

63-191  -  — ,  same  as  above,  with  certificate  from  Physik-Technische  Reichsanstalt 

Duty  Free 


63-193  LOW  TEMPERATURE  THERMOMETER,  stem  graduation  by  single  de¬ 
grees,  from  -100  to  10°  Centigrade;  without  certificate  .  .  .  Duty  Free 
63-194  -  — ,  same  as  above,  with  certificate  from  Physik-Technische  Reichsanstalt 

Duty  Free 

63-196  LOW  TEMPERATURE  THERMOMETER,  stem  graduations  by  single 
degrees,  from  -200  to  10°  Centigrade,  for  measuring  the  temperature  of 

liquid  air;  without  certificate  . Duty  Free 

63-197  -  — ,  same  as  above,  with  certificate  from  Physik-Technische  Reichsanstalt 

Duty  Free 


No.  63-155b 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


217 


SPECIAL  THERMOMETRIC  INSTRUMENTS 

DIFFERENTIAL  THERMOSCOPES 


No.  64-16  No.  64-20 


64-16  UNIVERSAL  AIR  AND  LIQUID  DIFFERENTIAL  THERMOSCOPE.  This  design,  a  modification 
according  to  our  specifications,  may  be  used  equally  well  for  indicating  the  temperature  of  liquids, 
as  in  comparing  temperature  of  two  neighboring  places.  Thus,  as  may  be  noted  from  our  illustra¬ 
tion,  the  thermoscope  bulbs  are  bent  downward  yet  opposite  the  small  table  which  is  designed 
especially  for  holding  the  source  of  radiant  energy.  The  illustration  shows  our  No.  61-100  Leslie’s 
Cube  in  position,  and  comparison  of  liquids  may  be  demonstrated  by  use  of  two  vessels  containing 
the  liquid,  the  bulbs  dipping  into  the  vessels.  The  bent  U-tube  contains  the  colored  liquid,  and  in 
a  tube  which  connects  the  two  limbs  is  a  stop-cock  by  which  the  liquid  in  each  limb  is  easily  brought 


to  the  same  level.  This  glass  part  is  mounted  in  a  frame  with  a  scale,  the  whole  mounted  on  a 
neat  base. 

Without  the  illustrated  Leslie’s  Cube .  $7.60 

64-20  DIFFERENTIAL  THERMOSCOPE,  for  indicating  a  difference  of  temperature  between  two  bulbs. 

The  apparatus  consists  of  two  bulbs  connected  by  a  U-tube,  from  which  air  has  been  expelled  by  boil¬ 
ing  before  sealing,  the  liquid  contained  therein  as  an  indicator.  This  tube  with  attached  bulb  is 
mounted  with  scale  on  an  upright  support .  1.96 


ii 

9 


64-30  AIR  THERMOMETER,  after  Rendtorff,  for  showing  expansion  of  air  by  heat. 

This  thermometer  consists  of  a  bulb  into  which  is  sealed  a  capillary  tube,  the  end  of  which 
tube  extends  nearly  to  the  bottom  of  the  bulb.  Through  the  bulb  and  sealed  into  the 
opposite  walls  is  a  wire  ofvhigh  resistivity.  Terminals  are  left  outside  the  bulb  for  con¬ 
nection  to  batterjr.  The  whole  apparatus  is  freed  from  air,  before  sealing,  by  boiling  the 
colored  liquid  contained  therein . 

64-36  AIR  THERMOMETER,  for  illustrating  gas  expansion,  of  glass,  with  two-inch  bulb  .  .  . 


2.26 
.1  7 


No.64-30 


2l8 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


64-65 


64-67 

64-69 


64-66 


64-66 

64-67 

64-70 


AIR  THERMOMETERS 


No.  64-66 


No.  64-70 


CONSTANT  VOLUME  AIR  THERMOMETER,  for  determining  the  coefficient  of  expansion  of  air, 
or  of  a  gas. 

This  apparatus  consists  of  a  rectangular  frame  with  the  scale  mounted  on  one  of  our  H-bases.  The 
air  thermometer,  fastened  by  a  protective  strip  of  wood,  is  adjustably  clamped  to  one  rod  and 
the  open  leveling  tube  similarly  mounted  and  clamped  to  the  other  rod.  The  open  lower  ends  of 
each  are  connected  by  the  finest  quality  of  flexible  rubber  tubing. 

This  instrument  is  substantially  constructed  throughout  and  handsomely  finished  in  nickel-plate  and 
japan.  It  has  been  designed  that  laboratories  may  have  at  a  reasonable  cost  an  instrument  capa¬ 


ble  of  accurate  determinations.  We  have  no  hesitancy  in  recommending  it  as  capable  of  results 
attained  by  instruments  of  double  the  cost. 

Complete  as  illustrated .  $8.60 

AIR  THERMOMETER  BULB,  for  attachment  to  above  stand  to  replace  breakage .  .76 

BOYLE’S  LAW  TUBE,  for  use  on  above  stand  in  determining  Boyle’s  Law.  This  tube  may  be 
mounted  in  place  of  the  air  thermometer  pictured  in  above  illustration.  For  apparatus  complete 

see  No.  41-110 .  1.26 

AIR  THERMOMETER,  after  Millikan,  Gale  and  Bishop,  Exp.  14,  for  determining  the  coefficient  of 
expansion  of  air. 


This  is  an  elementary  air  thermometer,  capable  of  a  fair  degree  of  accuracy.  It  consists  of  an  air 
thermometer  tube,  leveling  tube,  and  scale  mounted  to  a  backing  which  may  be  adjusted  along  the 
rod  of  the  tripod  stand  by  means  of  a  clamp  attached  to  the  backing.  The  lower  open  ends  of  the 
tubes  are  connected  by  our  finest  quality  flexible  antimony  rubber  tubing.  The  apparatus  is  dur¬ 


ably  finished,  the  metal  parts  in  bright  nickel  and  japan. 

Complete  as  illustrated .  3.36 

- ,  without  support .  1.66 

AIR  THERMOMETER  BULB,  as  used  in  above  apparatus . Each  .46 

CONSTANT  VOLUME  AIR  THERMOMETER,  highest  quality  constructed  by  one  of  the  most 

prominent  European  manufacturers  and  extensively  used  as  a  precision  instrument  .  .  Duty  free  .  .  . 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


219 


AN  IMPROVED  MINERALITE  THERMOPILE 


fa 


No.  64-100 


We  offer  in  this  series  of  Thermopiles,  instruments  of  two  sizes  which  cover  all  ranges  in  both  amperage  and 
voltage,  of  the  Bismuth  Antimony  type,  from  the  single  pair  to  120  pair. 

A  study  of  the  table  below  will  show  the  relative  strength  of  our  sizes  A  and  B  as  compared  with  the  Bismuth 
Antimony  Pile  of  twenty  pair,  which  is  usually  taken  as  the  standard  in  Thermo-electric  Measurement. 

The  advantages  of  the  Improved  Mineralite  Pile  are  much  greater  sensibility,  greater  mechanical  strength, 
and  greater  durability. 

In  preparing  the  data  given  in  Table  I  below,  we  have  used  a  unit  area  of  metallic  surface  kept  at  100°  Centi¬ 
grade  and  distant  from  the  Pile  10  centimeters.  Deflections  in  each  case  are  read  by  a  galvanometer  of  standard 
D’Arsonval  type.  In  Table  II,  the  source  of  heat  is  the  direct  rays  of  the  sun,  the  experiment  being  taken  on  a 
typical  Boston  winter’s  day. 

TABLE  I 

Unit  Area  Metallic  Surface  at  100°  Centigrade.  Ten  Centimeters  Distant  from  Face  of  Pile 


INSTRUMENT 

TIME 

30  Seconds 

1  Minute 

2  Minutes 

20  pair  Bismuth  Antimony 

9  Divisions 

11  Divisions 

10  Divisions 

Mineralite  A 

30  Divisions 

34  Divisions 

36  Divisions 

Mineralite  B 

45  Divisions 

52  Divisions 

55  Divisions 

TABLE  II 

Direct  Sunlight  as  Source  of  Heat 


INSTRUMENT 

TIME 

1  Minute 

20  pair  Bismuth  Antimony 

17  Divisions 

Mineralite  A 

83  Divisions 

Mineralite  B 

167  Divisions 

64-100  IMPROVED  MINERALITE  THERMOPILE  A  with  stand  . , . $11.76 

64-110  IMPROVED  MINERALITE  THERMOPILE  B;with  stand .  14.60 

OTHER  RADIOMETERS.  Section  61. 


220 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


THERMO-ELECTRIC  BATTERIES 


No.  64-127 

* 

Thermo-Electricity  has  been  a  matter  of  study  for  a  number  of  years,  but  the  principal  use  of  a  thermo-electric 
couple  or  a  thermopile  has  been  that  of  a  sensitive  radiometer.  The  new  thermo-electric  instrument  above  illus¬ 
trated  is  designed  for  practical  use,  —  that  of  a  thermo-electric  battery.  These  forms  are  of  simplified  construc¬ 
tion,  low-priced  and  with  highly  efficient  output.  With  the  larger  sizes,  small  machinery  may  be  operated,  incan¬ 
descent  lamps  lighted,  storage  batteries  charged,  etc.  For  experiments  in  electrolysis,  they  are,  perhaps,  unexcelled. 
From  the  fact  that  they  may  be  operated  instantly  and  need  no  attention,  their  popularity  in  this  country  and 
abroad  has  been  continually  increasing.  Each  battery  is  supplied  complete  with  burner. 

64-125  THERMO-ELECTRIC  BATTERY,  26  elements,  E.  M.  F.  1.8  to  2.2  volts;  current  strength  on  short 

circuit  3  to  4  amperes. 

Complete  with  Gas  Burner  . . Duty  Free  .  .  . 

64-125a  - ,  same  as  above,  but  with  Alcohol  Burner . Duty  Free  .  .  . 

64-126  THERMO-ELECTRIC  BATTERY,  similar  to  above,  but  larger,  38  elements,  E.  M.  F.  2.8  to  3.2 

volts;  current  strength  on  short  circuit  3  to  4  amperes. 

Complete  with  Gas  Burner  . Duty  Free  .  .  . 

64-126a  - ,  same  as  above,  but  with  Alcohol  Burner . Duty  Free  .  .  . 

64-127  THERMO-ELECTRIC  BATTERY,  similar  to  above,  but  larger,  50  elements,  E.  M.  F.  about  4.2 
volts;  current  strength  about  4  amperes. 

Complete  with  Gas  Burner  . Duty  Free  .  .  . 

64-127a  —  — ,  same  as  above,  but  with  Alcohol  Burner . Duty  Free  .  .  . 

64-128  THERMO-ELECTRIC  BATTERY,  extra  large,  100  elements,  E.  M.  F.  4  to  4.5  volts;  current 

strength  on  short  circuit  4  to  5  amperes. 

This  battery  is  especially  adapted  for  charging  a  7  to  10  ampere  storage  cell. 

Complete  with  Gas  Burner  . Duty  Free  .  .  . 

64-128a  - ,  same  as  above,  but  with  Alcohol  Burner . Duty  Free  .  .  . 


No.  64-160 

64-160  PORTABLE  INDICATING  ELECTRIC  PYROMETER  for  indicating  temperatures  not  exceeding 

2000  degrees  Fahrenheit  (1100  degrees  Centigrade). 

This  instrument  is  rugged  in  structure,  durably  and  handsomely  finished.  It  is  furnished  with  a 
base-metal  Thermo-couple  and  indicates  the  temperature  within  a  minute  or  two  after  the 
Thermo-couple  has  been  inserted  in  the  high  heat. 

With  Thermo-couple  and  15  feet  of  Flexible  Cable . . . 


$60.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


221 


EXPANSION  OF  MATTER 

LINEAR  EXPANSION  APPARATUS 


No.  65-10 

66-10  COWEN’S  LINEAR  EXPANSION  APPARATUS,  for  the  rapid  measurement  of  linear  expansion  of 
solids. 

The  apparatus  consists  of  a  multiplying  device  on  which  the  solid  in  the  form  of  a  tube  rests.  Any 
movement  of  the  tube  lengthwise  is  greatly  multiplied  and  accurately  indicated  on  a  graduated  dial. 
All  parts  are  accurately  fitted  and  handsomely  finished.  The  apparatus  occupies  a  small  space, 
yet  from  its  mechanism  presents  a  highly  scientific  appearance. 

Results  of  extensive  use  have  brought  out  the  following  features,  —  SIMPLICITY;  no  complicated 
mechanism  for  clamping  the  rod  and  measuring  same,  the  movement  lengthwise  merely  being 
multiplied  by  our  patented  device,  the  mechanism  of  which  can  readily  be  understood  by  even  the 
most  unscientific  mind:  ADAPTABILITY;  this  instrument,  taking  a  tube  of  any  length  from  20 
centimeters  up  and  any  diameter  desired:  ACCURACY;  in  the  shortest  time  possible  and  with  a 
minimum  of  trouble,  an  accuracy  in  excess  of  the  ordinary  form  of  linear  expansion,  is  possible 
with  this,  our  patented  design,  inasmuch  as  reasonable  errors  of  observation  cause  only  slight  errors 


in  final  determinations. 

Apparatus  complete,  including  one  brass  tube . $3.00 

66-11  STEEL  TUBE,  for  use  with  above .  .45 

65- 12  ALUMINUM  TUBE,  for  use  with  above .  .45 

66- 13  BRASS  TUBE,  as  used  in  above  .  .40 

65-14  GLASS  TUBE,  for  use  with  above .  .20 

65-16  GLASS  RESERVOIR  AND  STIRRER  after  Turner  and  Hersey,  Exp.  H023  . 25 


No.  65-17 

65-17  COWEN  COMPENSATION  APPARATUS,  as  designed  by  George  A.  Cowen  of  the  West  Roxbury 
High  School,  to  use  in  connection  with  apparatus  No.  65-10  in  demonstrating  the  effect  of  multiple 
bars  of  different  coefficients  of  linear  expansion  as  used  in  the  Compound  Pendulum. 

The  apparatus  is  simple  in  form,  as  shown  in  the  cut,  the  various  expanding  bars  -being  held  together 
with  two  brass  clamps  on  the  same  principle  as  the  multiple  bars  are  held  in  the  Compensated 
Pendulum. 

A  most  interesting  phenomenon  is  observed  when  the  steam  enters  from  the  steam  boiler.  The  tube 
which  is  reached  first  by  the  steam,  expands,  causing  the  pointer  to  make  rapid  movement  toward 
the  left.  When  the  steam  reaches  the  second  bar  of  the  system,  this  being  the  bar  of  greatest 
coefficient  of  expansion,  the  pointer  moves  to  the  right  to  and  well  beyond  the  starting  point. 
When  the  steam  reaches  the  third  bar  of  the  system,  it  will  again  move  to  the  left,  reaching  the  zero 
point  from  which  it  started  and  there  stop,  showing  successively  the  relative  expansion  of  the 
tubes  in  the  order  in  which  the  steam  strikes  them. 

We  recommend  that  this  piece  of  apparatus  be  placed  in  the  hands  of  the  individual  student  where 
possible,  although  the  effect  is  sufficiently  striking  to  serve  well  as  a  lecture  table  demonstration. 


Complete  as  illustrated .  $5.00 

65-18  COWEN  COMPENSATING  ATTACHMENT,  for  use  with  Cowen’s  Linear  Expansion  Apparatus 

No.  65-10 .  2.40 


222 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


T-BEAM  SERIES  LINEAR  EXPANSION  APPARATUS 
(LEVER  AND  MICROMETER  FORMS) 

The  advantages  of  this  type  of  apparatus  will  be  readily  seen  from  the  cut,  —  substantial  construction,  the 
ends  clamped  securely  to  the  table  avoiding  all  errors  due  to  the  supports  not  being  rigid,  the  distance  between  the 
supports  easily  varied  to  meet  varying  conditions.  The  metal  brace  between  the  two  uprights  formerly  used  has 
been  eliminated,  doing  away  with  the  unavoidable  error  arising  from  the  expansion  of  this  brace  by  the  heat  radi¬ 
ated  from  the  steam  jacket.  Please  note  that  the  supporting  ends  of  our  instruments  are  attached  by  the  well- 
known  Interlocking  T-beam  Attachments  to  the  standard  Basic  Clamps  “A,”  strong  and  rigid  clamps  which  hold 
the  apparatus  securely  to  the  table  top.  The  uniformly  accurate  results  which  these  instruments  give  are  due  to 
the  fact  that  all  possible  sources  of  error  have  been  carefully  worked  out  and  eliminated. 


65-20 

6-1000 

65-22 


T-BEAM  SERIES  LEVER  EXPANSION  APPARATUS,  complete  as  illustrated  without  Basic  Clamps 

T-BEAM  BASIC  CLAMP  “A,”  two  of  which  are  required  for  above  apparatus . Each 

LEVER ^FORM  LINEAR  EXPANSION  APPARATUS,  similar  to  No.  65-20,  but  designed  to  rest 
on  the  table.  A  nickel-plated  metal  brace  connects  the  two  uprights.  Complete  with  one  ex¬ 
pansion  rod . 


$3.25 

.94 

2.65 


65-25  T-BEAM  SERIES  MICROMETER  SCREW  EXPANSION  APPARATUS,  complete  as  illustrated 

without  Basic  Clamps .  $3.85 

6-1000  HARCOURT  UNIVERSAL  T-BEAM  BASIC  CLAMP  “A,”  two  of  which  are  required  for  above 

Each  .94 

65-27  MICROMETER  SCREW  LINEAR  EXPANSION  APPARATUS,  similar  to  No.  65-25,  but  de¬ 
signed  to  rest  on  the  table.  A  nickel-plated  metal  brace  connects  the  two  uprights  Complete 
with  one  expansion  rod .  4.60 

THE  IMPROVED  SPINE-SUPPORTED  LINEAR  EXPANSION  APPARATUS 

In  this  series  of  Linear  Expansion  Apparatus  we  wish  to  call  particular  attention  to  the  improved  method  of 
supporting  the  tube,  it  being  held  lengthwise  on  the  top  edge  of  a  substantial  oak  spine,  but  not  in  actual  contact 
with  the  wood.  The  design  is  such  that  the  drip  from  the  falling  water  or  the  radiated  heat  from  the  tube  intro¬ 
duces  no  error,  a  very  important  feature  in  all  designs  of  apparatus  for  determining  the  Coefficient  of  Linear  Ex¬ 
pansion. 

The  apparatus  is  offered  both  in  the  Lever  and  Micrometer  form. 


No.  66-30 

Patented  Sept.  7,  1906 

65-30  SPINE-SUPPORTED  LEVER  FORM  EXPANSION  APPARATUS,  complete,  including  Brass  Rod  $4.40 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


223 


66-40  SPINE  SUPPORTED  MICROMETER  SCREW  FORM  LINEAR  EXPANSION  APPARATUS,  for 

determining  the  coefficient  of  linear  expansion  of  a  rod. 

This  form  of  expansion  coefficient  apparatus  substitutes  a  micrometer  screw  in  place  of  lever  for 
reading  the  expansion.  A  lever  at  the  other  end  of  the  rod  facilitates  in  the  zero  readings,  indi¬ 
cating  positive  contacts  of  the  end  of  the  micrometer  screw  on  the  rod,  thus  avoiding  the  incon¬ 
veniences  of  electrical  connections  and  overcoming  absolutely  the  errors  to  which  the  electrical 
method  is  liable. 

Mounted  on  handsomely  finished  hardwood  support 

66-46  ALUMINUM  ROD,  for  use  with  Nos.  66-20  to  66-40 
66-46  IRON  ROD,  for  use  with  Nos.  66-20  to  66—40 

66-70  BRASS  TUBE  AND  POINTER  after  Millikan,  Gale  and  Bishop,  Exp.  15 . 


No.  66-80 


No.  66-80 


$4.60 

.46 

.40 

.66 


66-76  COMPOUND  BAR,  for  showing  unequal  expansion  of  metal. 

This  apparatus  consists  of  two  welded  pieces  of  metal,  iron  and  brass,  which  when  heated  will  show  their 
unequal  expansion  qualities  by  bending  in  the  form  of  an  arc,  the  inner  part  of  which  will  be  the 
metal  of  lesser  expansibility. 

Complete  as  illustrated,  with  handle  for  comfortable  heating .  $0.66 


66-80  COMPOUND  BAR  WITH  INDICATOR,  for  showing  the  unequal  expansion  of  two  metals. 

This  is  an  ingenious  device  for  registering  on  a  dial  the  expansion  of  the  metal  of  the  greater  expansi¬ 
bility  .  4.00 

65-110  GRAVESEND  BALL  AND  RING,  for  illustrating  expansion  of  metal  upon  application  of  heat  and 
contraction  upon  withdrawal. 

The  apparatus  consists  of  a  polished  metal  ball  and  a  ring  through  which  the  ball  at  ordinary  tem¬ 
perature  will  just  pass,  each  of  which  is  attached  to  a  metal  rod  with  handle  end. 

At  ordinary  temperature,  the  ball  will  just  pass  through  the  ring,  but  when  heated,  it  cannot  be 

forced  through.  Cooled  below  ordinary  temperature,  it  will  fit  loosely .  .98 

17-60  COMPENSATED  PENDULUM,  illustrating  method  of  time  compensation  by  application  of  un¬ 
equal  expansion  of  rods .  12.36 

65-80  TREVELYAN’S  ROCKER,  for  illustrating  that  musical  vibrations  are  maintained  by  communi¬ 
cation  of  heat. 

The  apparatus  consists  of  a  brass  rod  with  a  V  groove  milled  lengthwise.  To  this  rod  is  fastened 
a  metal  handle  with  ball  end.  When  this  bar  is  heated  at  some  point  below  the  melting  point  of 
lead  and  placed  so  that  the  edges  of  the  V  groove  rest  on  the  lead  casting  as  indicated,  the  bar  be¬ 
gins  to  emit  a  harsh  note.  This  note  may  be  made  to  rise  in  pitch  by  slightly  pressing  on  the  bar. 

Trevelyan’s  Rocker  with  Lead  Rest .  2.00 


224 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PACKARD’S 

BREAKING  BY  EXPANSION  AND  CONTRACTION  APPARATUS  No.  65-130 


No.  66-130 


No.  65-130  (Fig.  2)  .  No.  65-130  (Fig.  3) 


This  piece  of  apparatus  has  been  designed  to  demonstrate  most  effectively  the  power  exerted  by  an 
expanding  or  contracting  metal  bar.  The  expansion  is  obtained  by  a  burner  in  tube  form  indicated  in  the 
illustration.  The  power  exerted  by  the  expanding  or  contracting  rod  is  presented  most  strikingly  by  the 
breaking  of  a  steel  bar  placed  in  the  slot  in  the  end  and  at  right  angles  resting  against  knife  edge  supports. 

It  will  thus  be  seen  that  whether  the  rod  be  heated  by  the  tube,  or  allowed  to  contract  in  the  process 
of  cooling,  the  bar  will  be  broken  and  at  the  instant  of  breaking  the  lever  will  be  thrown  violently,  the  results 
being  therefore  striking  by  the  breaking  of  the  bar,  the  sudden  rising  of  the  pointer  and  the  noise,  leaving  no 
doubt  in  the  student’s  mind  that  great  force  has  been  exerted. 

In  addition  to  the  above  features  the  instrument  makes  a  most  satisfactory  lecture  table  piece  for 
teaching  briefly  but  quickly  the  principle  of  expanding  by  heat. 

The  substantial  construction,  careful  workmanship  and  correct  design  make  this  a  most  satisfactory 
lecture  table  demonstration  piece.  Twelve  steel  bars  for  breaking  supplied  with  each  instrument. 

Please  note  that  the  above  instrument  serves  to  teach  the  force  exerted  by  an  expanding  rod,  force 
exerted  by  a  contracting  rod  and  the  relative  amount  of  expanding  and  contracting  by  heat. 


Complete  as  illustrated 


58.75 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


225 


66-150 


No.  65-160 


No.  62-240 


HOPE’S  MAXIMUM  DENSITY  OF  WATER  APPARATUS  for  illustrating  the  point  of  Maximum 
Density  of  Water,  also  for  explaining  reason  why  the  surface  of  a  pond  may  be  covered  with  ice 
while  underneath  is  water. 

The  apparatus  consists  of  a  cylindrical  jar  in  the  sides  of  which,  near  top  and  bottom,  are  drilled 
holes  to  contain  sensitive  thermometers.  Around  this  jar  about  midway  between  these  holes  is 
sealed  a  spun  copper  ice  container. 

In  use,  the  jar  is  filled  with  water  sufficient  to  immerse  the  upper  thermometer  bulb.  A  freezing 
mixture  is  placed  in  the  copper  ice  container.  As  the  water  in  the  jar  cools,  the  density  is  in¬ 
creased,  the  more  dense  portion  sinking  to  the  bottom,  where  its  temperature  will  be  registered  by 
the  lower  thermometer.  It  will  be  noted  that  the  reading  of  this  thermometer  will  be  lower  than 
that  of  the  upper  until  4°  Centigrade  is  reached,  at  which  point  the  reading  will  remain  stationary, 
whereas  the  upper  will  continue  to  descend  until  0°  Centigrade  is  reached. 

Complete  as  illustrated,  with  rubber  stoppers  for  thermometers  but  without  thermometers  .  .  . 

THERMOMETERS.  Section  63. 


$5.00 


62-240 


DESPRETZ  WATER  THERMOMETER  for  indicating  cubical  expansion  of  liquid  or  for  determin¬ 
ing  the  maximum  density  of  water.  (See  Section  62.) . .  1.10 


No.  66-175 


i 


No.  65-170 


No.  66-180 


65-170 


65-175 


65-177 

65-180 


65-191 


FREEZING  BOMB,  illustrating  the  tremendous  expansive  force  exerted  as  water  freezes. 
Consists  of  a  cast-iron  sphere  cored  to  contain  about  2  ounces  of  water.  The  throat  is  tapped 
to  receive  a  screw  plug. 

When  filled  with  water  and  placed  in  freezing  mixture,  although  of  cast  iron,  this  bomb  will 
burst  from  the  tremendous  force  exerted  from  the  expansion  of  water  when  changing  from 

the  liquid  to  the  solid  state  . $0.95 

CHARLES  LAW  TUBE,  after  Hall  and  Bergen,  for  showing  that  under  constant  pressure 
different  gases  possess  the  same  coefficient  of  expansion. 

This  consists  of  two  tubes  of  capillary  bore,  connected  by  a  flexible  rubber  tubing.  One  of 
these  tubes  has  a  closed  end  and  contains  dry  air  which  extends  part  way  into  the  open  tube, 

in  which  is  an  indicating  globule  of  mercury  . . . 1.66 

Note.  The  use  of  this  tube  presupposes  an  equipment  consisting  of  a  Bunsen  Burner,  a  Hyp- 
someter,  an  Ice  Tray,  a  Meter  Rod,  and  a  Barometer.  For  these  instruments,  see  Index. 

LEVELING  TABLE  for  use  with  above  after  Hall  No.  52a . 1.60 

WATERMAN’S  CHARLES  LAW  TUBE  for  similar  use  as  above,  requiring  practically  the 
same  accessories. 

The  apparatus  consists  of  tube  of  capillary  bore,  one  end  of  which  is  sealed  and  contains  dry 
air  stoppered  by  a  globule  of  mercury.  This  tube  is  mounted  on  a  graduated  backing  for 

direct  measurement  of  air  expansion . 1.75 

VOLUME  COEFFICIENT  TUBE,  after  Millikan,  Gale  and  Bishop  (Experiment  14a) . 10 


226 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MEASUREMENT  OF  THE  QUANTITY 

OF  HEAT 

CALORIMETERS 

66-10  PARR’S  STANDARD  CALORIMETER 

for  determining  the  calories  of  heat  de¬ 
veloped  by  the  combustion  of  bitumi¬ 
nous  and  anthracite  coals,  lignites,  coke, 
etc. 

The  apparatus  consists  of  a  cartridge  in 
which  is  placed  the  combustible  material 
in  the  form  of  a  powder  and  mixed  with 
a  chemical  compound.  This  cartridge 
is  placed  in  a  measured  quantity  of  water 
in  an  insulated  calorimeter  can.  This 
calorimeter  can  is  contained  within  two 
insulating  vessels  with  air  spaces  be¬ 
tween.  The  pulley  noted  in  the  illus¬ 
tration  operates  the  cartridge  and  is  pro¬ 
vided  with  small  vanes  for  causing  a 
constant  uniform  stirring  of  the  water. 

This  pulley  may  be  driven  by  any  con¬ 
venient  means  at  hand.  The  illustra¬ 
tions  show  it  in  use  driven  by  Electrical 
Motor.  In  use,  the  coal  or  combustible  substance  is  ground  to  pass  through  a  100  mesh  sieve  and  a 
weighed  quantity  is  put  into  the  cartridge  together  with  a  chemical  compound.  A  measured 
quantity  of  water  is  then  placed  in  the  insulated  calorimeter  can.  The  stirrer  is  then  set  in  motion, 
operated  either  by  water  or  electric  power.  After  a  constant  temperature  has  been  obtained, 
ignition  is  effected  by  means  of  a  short  piece  of  hot  wire  dropped  through  the  stem  of  the  cartridge. 
Extraction  of  the  heat  is  completed  in  from  four  to  five  minutes.  The  maximum  reading  is  taken 
and  the  rise  of  temperature  multiplied  by  a  simple  factor  gives  the  heat  in  B.  T.  U.  per  pound  of  coal. 

The  complete  calorimeter  outfit  includes  a  fine  thermometer  graduated  to  14o°  F.  with  certificate 
of  accuracy,  a  two-liter  measuring  flask,  chemical  receptacle,  measuring  cup,  5-inch  100  mesh 
brass  sieve  with  bottom,  chemicals  sufficient  for  10  determinations,  pincers,  ignition  wire,  read¬ 
ing  lens,  and  camel’s  hair  brush  . $77.00 


No.  66-10 


No.  66-11 


66-11  PARR’S  STANDARD  CALORIMETER,  same  as  above,  but  equipped  for  electric  ignition  ....  $82.60 


66-12  WATER  MOTOR  AND  SUPPORT .  Extra  6.60 

66-13  ELECTRIC  MOTOR,  Lamp  series,  as  illustrated  above .  Extra  13.20 

66-14  SUPPORT  FOR  ELECTRIC  MOTOR,  as  illustrated  above .  Extra  2.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


227 


No.  66-35  No.  66-45  No.  66-60 


66-36  CINCINNATI  DOUBLE  WALL  CALORIMETER.  Consists  of  two  nickel-plated  brass  vessels, 
the  smaller  resting  on  a  supporting  ring  within  the  larger.  A  cover-with  holes  for  thermometer 


and  stirrer  is  supplied  with  the  outfit.  Complete . $1.40 

66-46  DOUBLE  WALL  CALORIMETER,  similar  to  above  but  larger,  and  spun  from  sheet  copper.  Heavily 
nickel-plated  inside  and  out.  A  cover  with  holes  for  thermometei  and  stirrer  is  supplied  with  the 
outfit.  Complete  .  2.96 


66-50  CULLER’S  CONDENSER  ATTACHMENT  for  use  with  above  or  other  calorimeters  to  determine 

Latent  Heat  of  Steam.  (See  Culler’s  “Laboratory  Manual  of  Physics,”  Experiment  XXHI)  ...  .96 


No.  61-206 


No.  66-65 


No.  66-75 


61-206  DOUBLE  WALL  CALORIMETER,  of  glass.  This  is  a  double-walled  vessel  with  outlet  for  evacuat¬ 
ing  chamber  between  walls.  It  will  be  found  invaluable  in  calorimetric  work . $3.26 


60-65  CALORIMETER  for  general  laboratory  usage  in  secondary  school  work  in  calorimetry. 

This  is  the  popular  nickel-plated  brass  calorimeter  used  so  frequently  in  determinations  of  specific 
heat,  latent  heat  of  melting  ice,  latent  heat  of  evaporization,  and  quite  frequently  for  dew  point 
tests.  Capacity  about  1  liter .  .60 

66-70  STIRRER  for  use  with  above  calorimeters . 20 

66-75  BUNSEN’S  ICE  CALORIMETER,  standard  form,  consisting  of  a  bulb  with  sealed-in  test  tube 

and  bent  mercury  tube . .  1.26 


228 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ELECTRIC  CALORIMETERS 


No.  66-100 


66-100  THE  IMPROVED  ELECTRIC  CALORIMETER,  designed  after  Stewart  &  Gee’s  “Practical  Phys¬ 
ics,”  Lesson  47.  This  instrument  was  designed  for  the  purpose  of  applying  Joule’s  Law  in  the 
determination  of  the  constant  of  a  Galvanometer,  consequently  the  best  possible  results  must  be 
obtained.  The  calorimeter  proper  is  of  the  form  shown  under  No.  66-106.  This  is  placed  in  the 
secondary  chamber  as  shown  in  the  illustration,  the  space  between  the  outer  chamber  and  the 
polished  surface  of  the  outer  wall  of  the  calorimeter  being  filled  with  an  insulating  compound 
composed  largely  of  magnesium  carbonate. 

Complete  as  illustrated . $9.90 


66-106  DOUBLE  WALL  ELECTRIC  CALORIMETER,  after 
Millikan  &  Mills’  “Electricity,  Sound  and  Light,”  (Ex¬ 
periment  4),  for  testing  the  calibration  of  a  voltmeter 
by  an  absolute  determination  of  potential  difference. 

This  calorimeter  consists  of  two  heavy  copper  vessels, 
the  inner  of  about  350  cubic  centimeters  capacity, 
insulated  from  and  supported  on  the  outer  by  a  fiber 
ring.  A  coil  of  fine  platinum  wire  is  wound  on  an  in¬ 
sulating  strip  which  is  connected  to  two  brass  rods. 

These  rods  extend  through  the  cover  and  end  in 
binding  post  terminals.  Two  holes  are  provided  in 
this  cover,  one  for  a  thermometer,  the  second  for  a 
handle  of  a  stirrer,  which  has  heat  insulating  end. 

Complete  as  illustrated . $6.86 

No.  66-110 

66-108  HEATING  COIL  ATTACHMENT,  mounted  on  fiber  cover.  This  attachment  is  intended  for  use 
with  No.  66-46  to  make  up  Electric  Calorimeter  above.  Teachers,  therefore,  who  already  have 
No.  66-46  Double  Wall  Calorimeter  need  order  this  attachment  only,  to  obtain  Electric  Calo¬ 
rimeter  No.  66-106  . $3.90 

66—110  STUDENTS’  ELECTRIC  CALORIMETER  for  determining  the  number  of  calories  of  heat  developed 
in  a  wire;  also  for  the  study  of  Joule’s  Law. 

The  apparatus  consists  of  a  glass  jar,  in  the  neck  of  which  is  placed  an  insulating  cover  bearing  two 
rods,  each  terminating  in  a  binding  post  connected  to  the  ends  of  a  coil  of  resistance  wire.  In  the 
center  of  this  cover  is  a  hole  for  the  thermometer. 

Complete  as  illustrated,  without  thermometer .  2.10 


No.  66-106 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


229 


JUNKER’S  CALORIMETER 


66-125  SIMPLIFIED  JUNKER’S  CALORIMETER  for  determin¬ 
ing  the  calorific  power  of  combustible  gases.  In  the  design 
above  illustrated  the  heated  gases  enter  the  inner  chamber  of 
a  triple-walled  vessel.  Within  this  chamber  these  gases 
come  in  contact  with  a  coil  of  copper  tubing  through  which 
a  current  of  water  continually  flows.  The  temperature  of 
this  water  is  noted  at  entering  as  well  as  upon  issuing  from 
the  coil,  by  the  means  of  the  thermometers  noted  in  the 
illustration.  In  order  to  determine  the  B.T.  U.,  the  quan¬ 
tity  of  gas  consumed  and  the  quantity  of  water  passed 
through  the  apparatus  must  be  determined  in  addition  to  the 
difference  in  temperature.  In  determining  the  quantity  of 
gas  consumed  we  advise  our  No.  66-130  Thorpe  Gauge. 

This  instrument  is  substantial  in  structure,  the  fundamental 
part  consisting  of  a  casting  to  which  are  mounted  the  two 
thermometer  tubes.  On  this  casting  is  mounted  a  double- 
walled  metal  chamber  surrounded  by  an  insulating  compound. 
The  ends  of  the  copper  circulating  coil  supported  from  above 
to  the  inner  metal  vessel  are  connected  through  the  casting  to 
the  thermometer  tubes.  The  instrument  may  be  mounted 
on  our  special  stand  as  illustrated  or  may  be  attached  to  any 
tripod  stand  by  means  of  a  clamp. 

Simplified  Junker’s  Calorimeter  only . 


$14.40 


No.  66-125 


66-130  THORPE  GAUGE  for  measuring  either  pressure  of  gas  or  rate  of  gas  flow. 

To  read  pressure  of  gas  screw  cap  down  over  outlet  at  the  top  and  connect  gas  supply  to  the  inlet. 

Index  on  left  scale  gives  reading  of  pressure  in  inches  of  water.  With  cap  removed  from  outlet 
and  gas  allowed  to  flow  through  the  gauge,  the  indicator  registers  on  right  hand  scale  the  rate  of 
flow  of  the  gas  in  cubic  feet  per  hour  .  .  .  .- . . $12.00 


SUBSTANCES  FOR  SPECIFIC  HEAT  DETERMINATIONS 


66-170  LEAD  CYLINDER  with  CONICAL  TOP,  weight  approximately  650  grams 


$0.66 


66-175  LEAD  SHOT . Per  Pound  .15 

66-177  COPPER  SHOT . Per  Pound  .66 


66-179  ALUMINUM  SHOT . Per  Pound 

66-181  GLASS  BEADS  . Per  Pound 


66-200  TYNDALL’S  SPECIFIC  HEAT  APPARATUS  for  qualitative  determi¬ 
nation  of  the  comparative  specific  heats  of  different  metals. 

The  apparatus  consists  of  a  tripod  on  which  is  supported  a  disc  of  paraf¬ 
fine,  5  balls  of  different  metals  with  handle  for  holding  balls  while 
heating  them,  and  a  tin  plate  for  casting  new  paraffine  discs.  The  balls 
may  be  heated  either  in  boiling  water,  or  by  the  flame  from  a  Bunsen 
burner,  or  spirit  lamp  at  the  intersection  of  the  rods  bearing  the  balls. 

Apparatus  complete  as  above  described . 


1.05 

1.00 


1.55 


No.  66-200 


230 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MECHANICAL  EQUIVALENT  OF  HEAT 

APPARATUS 


No.  67-20 


The  design  of  the  instrument  was  worked  out  at  the  Cavendish  Laboratory  in  Cambridge. 
In  operation  it  utilizes  the  principle  of  heating  a  given  quantity  of  water  by  friction,  both  the  water 
and  the  friction  surfaces  being  placed  in  a  carefully  insulated  calorimeter,  all  sources  of  error  either 
being  eliminated  or  accurately  accounted  for. 

Until  the  outbreak  of  the  European  war  this  instrument  was  imported  from  Europe.  As  a 
product  of  our  own  factory  we  call  particular  attention  to  features  of  prime  importance  which 
have  been  taken  into  consideration  in  its  manufacture. 


The  vertical  shaft  is  most  carefully  centered  so  that  the  friction  unit 
rotates  in  a  definite  plane. 

The  tapered  surfaces  of  the  hollow  truncated  cones  are  hand  finished  to 
assure  absolute  uniform  contact. 

To  prevent  radiations,  not  only  are  the  cones  carefully  insulated  from  the 
casing,  but  also  an  ample  air  jacket  is  provided. 


Apparatus  complete  with  detailed  laboratory  directions  and  ten  feet  Round  Leather 
Belting  with  Patent  Belt  Fastener . 


$27.80 


For  Drive  Wheels  and  Driving  Mechanism  see  Section  21 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


231 


No.  67-25 


No.  21-120 


67-25  DOUBLE  INSULATION  METAL 
CAPPED  MECHANICAL  EQUIV¬ 
ALENT  OF  HEAT  TUBE,  after  Mil¬ 
likan,  Gale  and  Bishop  (Experi¬ 
ment  20).  j  2jg| 

This  tube  is  a  full  meter  in  length, 
built  up  from  heavy  corrugated 
board  covered  inside  and  out  with 
tough  wrapping  paper,  thus  afford¬ 
ing  ample  air  insulation. 

The  ends  of  the  tube  are  closed  by 
cork  stoppers  and  close-fitting  metal 
screw  caps.  This  tube  must  not  be 
confused  with  those  of  the  cheaper 
construction . .  $0.70 


21-120  TYNDALL’S  HEAT  BY  FRICTION  APPARATUS  for  illustrating  with 
Rotator  the  heat  caused  by  friction  on  a  brass  tube  while  it  is  rotating 
rapidly  .  2.00 


No.  67-50 


67-50  FIRE  SYRINGE,  illustrating  the  production  of  heat  by  the  rapid  compression  of  gases. 

This  apparatus  consists  of  a  heavy  brass  cylinder,  about  20  centimeters  long,  provided  with  tightly 
fitting  piston.  On  the  end  of  this  piston  is  a  holder  for  a  small  piece  of  tinder.  This  cylinder  is 
mounted  on  a  convenient  foot  rest. 

In  use,  a  small  tuft  of  tinder  is  placed  in  the  holder  on  the  piston  and  moistened  with  either  ether  or 
carbon  disulphide  that  the  experiment  may  be  more  effective.  If  now  the  piston  is  driven  rapidly 
to  the  bottom  of  the  cylinder,  the  compression  of  the  air  generates  heat  sufficient  to  set  fire  to  the 
tuft  of  tinder. 

Complete  with  piece  of  tinder . $1.76 


HOT  AIR  AND  GAS  ENGINES 


’  No.  68-15 

68-15  HOT  AIR  MOTOR  for  use  in  schools  and  colleges  in  the  study  of  air  expansion  motors;  also  readily 
adapting  itself  to  the  operating  of  small  machinery  models,  etc. 

This  is  an  air-cooled  motor  with  adjustable  bearings  and  runs  smoothly  and  silently.  It  is  18  inches 
long  by  6  inches  diameter,  weight  about  16  pounds.  The  fly  wheel  has  a  diameter  of  6  inches  and 
pulley  of  \\i  inches. 

This  engine  may  be  run  on  either  gas  or  alcohol  and  either  types  of  burners  will  be  supplied  as 


requested  . $15.00 

68-30  HORIZONTAL  HOT  AIR  ENGINE.  This  is  a  design  illustrating,  in  a  similar  manner  as  No.  68-16, 
the  principle  of  air  expansion  motors.  It  is  of  simple  design,  but  will  readily  operate  from  the  heat 
of  a  small  alcohol  lamp .  3.75 


232  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  68-40 


68-40  GAS  ENGINE,  illustrating  motive  power,  operated  by  gas  explosion. 

This  is  a  small-sized  model  made  of  iron  and  brass.  It  is  about  6  inches  long,  3  inches  wide,  and  weighs 
3  pounds.  Speed  varies  from  200  to  700  R.  P.  M.;  enameled  and  nickel-plated. 

This  engine  will  be  found  an  excellent  model  for  demonstration. 

Complete  with  directions . 


68-60  THE  IMPROVED  GAS  ENGINE  WITH  SPARK  ADVANCING  AND  SPARK  RETARDING  DE¬ 
VICE.  The  model  above  illustrated  represents  in  section  a  four-cycle  commercial  gas  engine.  As 
may  be  noted,  all  parts  are  represented  in  their  proper  positions  and  may  be  shown  in  actual  oper¬ 
ation  by  merely  turning  a  crank,  the  movement  of  parts  being  caused  by  a  succession  of  gears. 

The  model  is  complete  with  all  essential  parts,  —  exhaust  and  intake  valves,  piston  head,  spark  plug, 
etc.,  all  being  shown  of  sufficient  size  for  classroom  demonstration.  By  an  ingenious  method  of 
construction  partially  noted  in  illustration  we  are  enabled  to  show  the  proper  moment  of  ignition 
giving  rise  to  compression,  if  the  secondary  of  a  Ruhmkorff’s  coil  be  connected  in  series  with  the 
spark  plug. 

This  engine  is  of  rigid  construction,  scientific  in  every  detail,  and  handsomely  finished  throughout,  the 
finish  of  the  different  parts  being  such  as  to  accentuate  the  parts  desired.  It  is  mounted  on  a  neatly 
finished  hardwood  base . 


$3.15 


$7.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


233 


69-10 


69-20 


69-30 


STEAM  ENGINES 


STEAM  ENGINE  MODELS 


ii'ii 


No.  69-20 

WOLLASTON  STEAM  ENGINE,  a  simple  model  to  illustrate  the  expansive  force  of  steam. 

This  apparatus  consists  of  a  vessel  as  illustrated,  in  the  neck  of  which  is  provided  a  close-fitting  piston. 
In  use  water  is  placed  in  the  bulb  and  heated  until  steam  is  formed.  Steam  will  force  the  piston  up 
the  tube.  If,  now,  the  steam  is  condensed  by  plunging  the  bulb  in  cold  water,  the  atmospheric 
pressure  will  force  the  piston  back . 

STEAM  CHEST  MODEL.  This  is  an  interesting  model  of  a  simple  steam  chest,  demonstrating  the 
opening  and  closing  of  the  port  holes  by  means  of  the  slide  valve. 

The  apparatus  consists  of  a  nickel-plated  housing  with  glass  window  through  which  may  be  seen  a 
working  model  of  a  steam  chest.  By  means  of  a  thumb  screw  at  the  back,  the  slide  valve  may  be 
worked  as  desired,  demonstrating  the  closing  and  opening  of  the  port  holes. 

This  is  a  handsomely  finished  instrument  constructed  on  pedagogical  lines.  It  will  be  found  very 
valuable  in  the  lecture  hall  in  that,  during  the  study  of  the  large  engines,  this  little  instrument 
may  be  passed  around  the  class . 

SECTIONAL  MODELS  OF  STEAM  ENGINES 


No.  69-30 


SECTIONAL  MODEL  OF  A  STEAM  ENGINE.  A  complete  model  of  the  locomotive  showing 
clearly  the  movements  of  slide  valve,  piston,  eccentric,  reversal  of  steam  by  means  of  link  motion  and 
“cut  off.”  All  parts  are  carefully  fitted  and  adjusted  and  have  been  finished  to  accentuate  the 
different  parts.  Though  the  size  is  sufficient  for  class  demonstration,  it  is  advised  that  a  pupil  use 
this  model  for  the  study  of  the  functions  and  relations  of  the  different  parts.  As  there  is  no  com¬ 
plicated  mechanism,  the  pupil’s  understanding  of  the  steam  engine  is  complete  after  a  short  study 
of  the  movements  imparted  to  the  different  component  parts  by  rotating  the  fly  wheel  a  few  times. 

Mounted  on  a  neatly  finished  wooden  base . 


No.  69-10 


$1.45 


3.25 


$2.65 


234  L .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  69-35 

69-36  THE  IMPROVED  EIGHTEEN-INCH  SECTIONAL  MODEL  OF  A  STEAM  ENGINE.  This 
model  takes  the  place  of  the  10-inch  model  which  was  formerly  made.  All  the  parts  are,  of  course, 
correspondingly  larger  and,  consequently,  of  correspondingly  greater  educational  value,  since  the 
new  model  is  designed  for  use  on  the  lecture  table. 

Great  care  has  been  exercised  in  making  all  the  parts  in  a  form  to  resemble  as  nearly  as  possible  similar 
parts  in  the  commercial  engine  of  locomotive  type.  The  sectional  view,  as  is  indicated  in  the  cut, 
shows  the  steam  chest,  cylinder,  piston,  and  valves  in  vertical  section  through  the  center.  Other 
features  are  shown  sufficiently  “off  set”  not  to  interfere  with  their  resemblance  to  the  actual 
working  engine. 

The  size  of  this  model,  being  18  inches  long  and  9  inches  high,  renders  it  particularly  well  adapted 
to  lecture  table  work.  In  order  to  assist  in  the  easy  differentiation  of  all  the  essential  parts  care  has 
been  exercised  in  the  proper  coloring  so  as  to  make  the  essential  features  stand  out  clear  and  sharp. 

Engine  is  mounted  on  a  substantial  hardwood  base,  the  entire  instrument  being  finished  so  as  to  give 
the  most  pleasing  appearance  without  interfering  with  its  educational  value . 


No.  69-40 

69-40  PROJECTION  HORIZONTAL  MODEL  OF  A  STEAM  ENGINE.  The  working  parts  of  this  model 
are  about  the  same  size  as  the  vertical  model  shown  above,  but  so  designed  that  they  can  be 
projected  on  the  screen  by  means  of  the  opaque  projector,  —  a  valuable  feature,  particularly  in 
lecture  rooms  accommodating  a  larger  number  of  students  than  can  readily  examine  closely  the 
18-inch  model. 

The  essential  features  are  carefully  differentiated  by  color  effect  so  as  to  give  the  most  striking  ap¬ 
pearance  and  easy  differentiation  on  the  screen. 

The  mounting  is  most  substantial;  workmanship  is  high  grade  throughout . 


$6.76 


$12.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


235 


No.  69-50 


€9-60  4-FOOT  MODEL  OF  A  STEAM  ENGINE,  after  design  suggested  by  Mr.  F.  R.  Miller,  English 
High  School,  Boston,  Mass. 

This  exceedingly  large  model  has  all  the  working  parts  of  such  generous  proportions  and  open  con¬ 
struction  that  every  student  in  a  large  lecture  hall  will  be  able  to  see  the  essential  features  easily. 
It  will  thus  be  seen  that  this  instrument  in  demonstration  work  will  do  for  the  large  lecture  room 
-  what  No.  69-36  does  for  the  small  one. 


The  drive  wheel  or  fly  wheel  has  been  omitted  from  this  model,  for  the  reason  that  it  would  of  neces¬ 
sity  be  of  such  large  proportions  as  to  make  the  entire  model  altogether  too  difficult  to  handle  and 
care  for. 


No.  69-66 


69-56  LOCOMOTIVE  CHART,  designed  particularly  for  hanging  permanently  on  the  wall  of  either  lec¬ 
ture  room  or  laboratory.  The  parts  are  so  clearly  indicated  as  to  serve  admirably  for  a  detailed 
study  of  the  parts  of  the  modern  locomotive.  The  sectional  view  shows  240  parts  all  named  and 
numbered.  It  gives,  in  addition,  complete  information  regarding  the  various  details  of  steam 
engines  in  general  and  locomotives  in  particular. 

Mounted  on  heavy  cardboard  with  eyelets  for  hanging . 


$27.60 


$2.26 


236  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  69-75 


No.  69-85 


63-75  WORKING  STEAM  ENGINE,  of  small  size,  for  use  with  Steam  Boiler  No.  60-366  and  consequently 
designed  to  work  on  exceedingly  low  pressure,  operating  smoothly  without  load,  on  two  inches  of 
mercury  pressure. 

It  is  a  compact,  durably  built,  and  substantial  little  engine.  The  factj  that  practically  all  schools 
are  provided  with  inexpensive  means  of  obtaining  adequate  steam  pressure  such  as  the  Steam  Boiler 
or  Hypsometer  above  referred  to,  makes  this  engine  of  very  wide  use. 

The  mechanical  or  power  advantage  of  working  as  a  high  or  low  pressure  engine  is  readily  demon¬ 
strated,  the  low  pressure  results  being  obtained  either  by  connecting  the  exhaust  to  a  condensing 
chamber,  or  working  it  in  connection  with  the  air  pump. 

As  will  be  noted  from  the  illustration,  the  engine  is  mounted  on  a  substantial  iron  base,  presenting 

very  much  the  appearance  of  the  commercial  power  engines . . $4.85 

V 

69-85  WORKING  MODEL  STEAM  ENGINE.  The  model  consists  of  a  boiler  and  an  engine  both  mounted 
on  a  nickel-plated  iron  base  the  edges  of  which  are  polished.  This  engine  runs  rapidly  and  easily, 
each  engine  being  thoroughly  tested  before  packing  and  fully  warranted.  Complete  with  explicit 
directions  for  use  and  care,  in  a  wooden  lock  corner  box .  7.40 


Nos.  69-116  to  69-117 

69-115  ONE-QUARTER  HORSE-POWER  HORIZONTAL  CORLISS  ENGINE,  cylinder  1^X2  inches; 

bed  12  inches  long  by  7  inches  wide;  fly  wheel  6  inches  in  diameter . $24.60 

69-117  ONE-HALF  HORSE-POWER  HORIZONTAL  CORLISS  ENGINE,  cylinder  1%  X  3  inches; 

bed  23^  inches  long  by  13)4  inches  wide;  fly  wheel  10  inches  in  diameter  by  2-inch  face;  approxi¬ 
mate  weight  40  pounds . 66.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


237 


STEAM  POWER  PLANTS 


No.  69-122 


69-120  STEAM  BOILER  AND  ENGINE.  The  pedagogic  merit  of  a  working  demonstration 
Steam  Boiler  and  Engine  of  commercial  type  and  of  sufficient  power  to  be  of  practical 
value  will  be  readily  appreciated.  Models  are  excellent  and  perhaps  necessary,  but  the 
wide-awake  student  is  not  satisfied.  He  desires  an  actual  operating  machine  of  commer¬ 
cial  type. 

Our  outfit,  weighing  175  pounds,  consists  of  a  commercial  34  H.  P.  Engine  mounted  on 
same  base  with,  and  connected  to,  a  commercial  34  H.  P.  Boiler. 

The  Engine  is  of  the  standard  Corliss  Type,  cylinder  1J4  inches  by  2  inches;  bed  12  inches 
long  by  7  inches  wide;  fly  wheel  6  inches  in  diameter.  It  is  carefully  designed,  and  no 
efforts  are  spared  in  its  construction  to  make  a  practical  engine  of  pleasing  appearance. 

It  is  provided  with  attachments  to  take  up  wear  and  maintain  adjustments. 

The  Boiler  is  of  the  Vertical  Tubular  Type,  10  inches  in  diameter,  height  over  all  21  inches, 
with  a  water  jacket  fire-box  and  twenty  %-inch  seamless  drawn  brass  tubes,  each  1034 
inches  long.  Shell  is  of  j^-inch  wrought  iron,  lap  welded,  the  upper  and  lower  parts  of 
best  grade  iron;  the  casing  and  the  stack  are  of  Russia  iron,  a  thoroughly  practical 
machine  tested  to  200  pounds  per  square  inch.  Steam  pressure  up  to  80  pounds  may  be 
utilized.  It  is  equipped  with  gas  burner  of  ample  size,  adapted  especially  to  the  work. 

(For  further  description  and  price  see  following  page). 


238 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


The  Base  is  of  cast  iron  of  ample  dimensions  for  both  Boiler  and  Engine.  It  is  neatly  finished. 

Engine  and  Boiler  are  firmly  attached  and  all  connections  made.  The  boiler  is  completely  equipped 
with  necessary  valves  and  gauges  so  that  all  that  is  necessary  to  start  operation  is  to  fill  the  boiler 
with  water  to  the  proper  height  as  seen  by  the  water  gauge,  connect  burner  to  gas  main,  and  gen¬ 
erate  the  steam. 

Illustration  is  that  of  No.  69-122  following,  but  the  outfit  described  under  this  number  is  the  same 

as  illustration  except  that  dynamo  is  not  furnished . $74.50 

69-122  STEAM  AND  ELECTRIC  POWER  PLANT.  Frequent  calls  have  been  made  for  an  outfit  which 
would  illustrate  the  generation  of  electric  power.  By  referring  to  the  illustration  it  will  be  noted 
that  we  have  attached  on  the  same  base  with  the  engine  and  boiler  above  listed  a  generator  of 
sufficient  capacity  to  demonstrate  the  principles  involved.  This  generator  is  of  commercial  type,  36 
watts  capacity  (6  volts,  6  amperes).  It  is  direct  belted  and  even  with  the  small  pressure  of  30 
pounds  may  be  run  to  its  full  speed  of  2200  R.  P.  M. 

Power  Plant  complete,  as  illustrated . 88.75 


STEAM  BOILERS 


The  commercial  type  engines  previously  listed,  pages  236  and  237,  require  steam  pressure.  To  satisfy  this  re¬ 
quirement  we  offer  one-quarter  and  one-half  H.  P.  boilers  of  a  convenient  size  and  commercial  type  selected  from 
this  country’s  manufactures  as  having  the  best  educational  value.  Each  boiler  is” equipped  with  a  steam  gauge  and 
safety  valve,  a  water  gauge  and  three  gauge  cocks,  with  valves  on  steam  and  water  pipes. 

Steam  boilers  of  this  type  are  given  a  prominent  place  in  laboratories  where  the  practical  nature  of  Physics  is 
stressed.  The  two  sizes  below  develop  energy  sufficient  to  run  the  ordinary  demonstration  models.  Larger  sizes 
will  be  quoted  and  furnished  on  application.  Each  boiler  is  complete  with  burner  all  ready  for  connection  to  source 
of  gas  supply  and  since  they  are  tested  to  withstand  pressures  of  practically  one  hundred  per  cent,  beyond  pressures 
ordinarily  required,  there  is  positively  no  danger  in  continuous  use,  especially  since  each  boiler  is  equipped  with  a 
safety  valve. 

Installations  have  been  made  and  these  boilers  have  been  found  entirely  satisfactory  in  the  following  ways: 

1.  Study  of  generation  of  steam  and  the  value  of  its  energy  commercially,  as  the  motive  force  in  run¬ 

ning  engines,  etc. 

2.  Study  of  boiler  construction  as  employed  commercially. 

3.  Study  of  functions  of  each  attachment,  valves,  cocks,  gauges,  safety  valves,  etc.,  and  why  necessary. 

4.  Study  of  Bourdon  Gauge  in  actual  use. 

5.  Determining  temperature  of  live  steam. 

6.  Source  of  live  steam  for  a  great  number  of  practical  experiments  in  Physics,  Chemistry  and  Biology. 

As  a  source  for  experiments  illustrating  rise  in  boiling  point  due  to  increase  of  pressure,  source  in 
determining  expansion  coefficient,  a  source  for  running  steam  baths  in  chemistry,  in  distillations,  in 
evaporations,  etc.,  etc.,  these  boilers  will  be  found  of  exceptional  value. 

69-125  ONE-QUARTER  HORSE-POWER  BOILER,  selected  as  best  adapted  not  only  to  furnish  steam 
pressure  to  run  our  Steam  Engine  No.  69-120,  but  as  a  boiler  of  complete  adaptability  to  general 
purposes.  Complete  with  improved  Gas  Burner . $37.76 

69-130  ONE-HALF  HORSE-POWER  BOILER,  similar  to  above.  Complete  with  improved  Gas  Burner  .  63.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


239 


No.  70-10 

70-10  HELIOPTICON  OR  SUNLIGHT  PROJECTOR.  This  instrument  consists  of  a  square  metal  plate 
in  which  is  fitted  a  large  flat  ring  to  which  is  fastened  a  long  mirror  by  special  patent  hinge.  This 
mirror  is  arranged  for  adjustment  to  any  angle  with  the  plate  by  a  large  screw  which  passes  through 
the  lower  portion  of  the  ring.  This  ring  also  carries  a  condensing  lens,  in  cell,  and  a  metal  handle 
by  which  the  ring  and  its  attachments  are  turned  in  a  vertical  plane.  A  combination  of  movements 
enables  the  mirror  to  be  adjusted  to  reflect  a  beam  of  sunlight  in  one  direction  and  keeps  it  in  posi¬ 
tion  with  but  slight  attention.  Two  parallel  tubes  pierce  the  metal  plate  below  the  ring  and  are 
held  firmly  by  clamping  screws.  This  tube  track  forms  a  light  but  rigid  bench  for  the  slide  stage  and 
objective  carrier.  It  may  also  be  used  for  an  optical  bench. 

Heliopticon  as  above  described,  including  J^-size  objective,  one  inch  condensing  lens,  and  slide 

carrier .  $25.00 

70-16  PORTE  LUMIERE  for  securing  parallel  beams  of  light.  This  instrument  is  a  “Sunlight  Projector”  9.00 

70-16  ADJUSTABLE  SLIT  DIAPHRAGM  for  use  with 

heliopticon  for  securing  a  rectangular  beam  of  light  1.60 

70-17  CYLINDRICAL  DIAPHRAGM  for  use  with  heliopticon 
with  five  graded  openings  for  securing  pencils  of 
light .  1.60 


LIGHT 

SOURCES  OF  LIGHT 


70-20 


70-22 


UNIVERSALLY  ADJUSTABLE  HELIOSTAT  WITH 
CLOCK  WORK.  The  instrument  illustrated  pictures 
a  heliostat  capable  of  universal  adjustments  to 
any  position.  It  is  manufactured  by  one  of  the 
leading  instrument  makers  of  Europe  whose  guaran¬ 
tee  is  sufficient  recommendation  of  its  quality.  It  is 
handsomely  finished  throughout  and  capable  of  very 
efficient  service.  Diameter  of  mirror  10  centimeters. 
With  each  heliostat  is  furnished  a  black  and  a  silvered 
mirror  and,  in  addition,  a  secondary  mirror  on  stand. 

Duty  Free 

HELIOSTAT,  same  as  above,  but  diameter  of  mirror 
5  centimeters  . Duty  Free 


74.00 

54.00 


No.  70-20 


PARAFFINE  CANDLES  for  use  in  photometric  work  as  source  of  light. 
These  candles  are  of  standard  quality  and  are  furnished  in  two  sizes: 


70-50a  Sixes  (six  to  the  pound) . Per  Dozen  .33 

70-60b  Twelves  (twelve  to  the  pound) . Per  Dozen  .20 


STANDARD  CANDLES.  See  Section  71. 


240  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  70-70 


No.  70-90 


No.  70-92 


70-70  KEROSENE  LAMP  AND  METAL  BOUND  ASBESTOS  CHIMNEY  for  furnishing  source  of  light 

in  photometric  experiments. 

This  consists  of  a  small  brass  kerosene  lamp,  with  wick  and  chimney.  In  order  to  furnish  merely  a 
beam  of  light  and  not  diffused  rays,  an  asbestos  chimney  withjsmall  opening  is  supplied  in  addition 
to  the  glass  chimney . $0.50 


70-72  KEROSENE  LAMP  only,  with  wick  and  glass  chimney .  $0.32 

70-73  METAL  BOUND  ASBESTOS  CHIMNEY,  only . 18 

70-90  ILLUMINATING  BURNER  FOR  GAS  for  laboratory  tables.  Con¬ 
sists  of  a  burner  tube  12  inches  high  mounted  on  heavy  iron  base  .  .80 

70-92  LOW  FORM  ILLUMINATING  BURNER,  curved  tube  fitted  with 
illuminating  tip. 

This  burner  will  be  found  very  convenient  for  use  with  optical  benches  .65 


No.  70-95 


70-96  MONOCHROMATIC  FLAME  BURNER.  Gases  of  various  substances 
generate  in  the  glass  cell  and  intermingling  with  the  illuminating  gas 


give  to  the  Bunsen  flame  the  distinct  monochromatic  flame  desired. 

Complete  as  illustrated .  $2.25 

70-110  ELECTRIC  LAMP,  table  size,  adjustable  from  12  to  18  inches,  made 
of  polished  brass,  nickel-plated. 

Complete  as  illustrated .  9.76 

70-112  GAS  LAMP,  similar  to  above,  but  arranged  for  burning  illuminating 
gas- 

Complete  with  Argand  Burner  and  six  feet  of  rubber  tubing,  with 

goose-neck  connection,  stand  adjustable  from  12  to  18  inches  .  .  .  9.76 

70-116  KEROSENE  LAMP,  similar  to  above,  but  arranged  with  reservoir 
for  oil. 

Complete  .  9.75 


No.  70-110 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


241 


LILLIPUTIAN  PROJECTING  LAMP 


The  Lilliputian  Projection  Lamp  was  designed  for  the  purpose  of  giving  an  intense  beam  of  parallel  rays  espe¬ 
cially  suited  for  work  in  the  physical  lecture  room.  It  has  also  been  adapted  for  transparent  projections  for  use  where 
ready  and  easily  operated  lantern  outfit  is  desired.  The  occasion  for  offering  this  apparatus  arose  from  the  difficulty 
of  handling  larger  outfits  in  a  way  to  most  readily  give  desired  results  in  physical  experiments. 

A  Projection  Lantern  using  from  12  to  15  amperes  of  current  must  necessarily  require  a  rheostat  of  ample  pro¬ 
portions,  a  housing  for  the  lamp  designed  to  properly  care  for  the  heat  generated,  and  a  condensing  system  of  sufficient 
size  for  producing  a  picture  from  12  to  16  feet  in  diameter  at  considerable  distance  from  the  lamp.  It  is  apparent 
that  an  apparatus  designed  for  this  work  cannot  be  readily  used  on  the  lecture  table  where  an  intense,  small  parallel 
beam  of  light  only  is  required.  To  meet  this  requirement,  a  small  lamp  with  automatic  feed  is  supported  with  a 
simple  rheostat  on  an  adjustable  upright  stand. 

The  condenser,  being  small  and  placed  close  to  the  arc,  uses  a  relatively  large  proportion  of  the  light  rays.  The 
rays  emerging  from  the  condenser  are  parallel,  forming  an  intense  beam  about  3  centimeters  in  diameter. 

The  current  required  is  only  1.5  amperes  at  110  volts  pressure.  The  form  of  lamp  above  illustrated  can  only 
be  furnished  for  direct  current. 

The  great  variety  of  uses  to  which  such  an  apparatus  can  be  put  will  be  apparent  at  once  to  those  who  have 
long  felt  the  need  of  such  a  source  of  light  in  lecture  table  work.  As  may  be  noted,  the  instrument  is  entirely  self- 
contained.  The  housing  is  adjustable  in  height.  The  necessary  resistance  is  mounted  on  one  of  the  legs  of  the 
tripod  base  and  binding  posts  for  connections  to  circuit  on  the  other  legs.  Close  observation  of  scientific  requirements 
has  enabled  the  manufacturers  to  furnish  a  lamp  that  may  be  readily  moved  from  place  to  place,  —  one  that  al¬ 
lows  of  universal  adjustment  both  as  to  position  of  lamp  and  direction  of  the  rays  of  light  proceeding  from  the  ap¬ 
paratus. 

Although  exceedingly  compact,  renewal  of  carbons  is  simple.  Their  position  within  the  housing  is  readily  noted 
through  the  window  provided. 

70-126  LILLIPUTIAN  PROJECTION  LAMP,  as  illustrated,  with  resistance  on  stand  for  direct  current  of 


1.5  amperes  at  110  volts,  with  ten  extra  carbons . Duty  Free  .  .  . 

70-126  -  — ,  same  as  above,  but  with  resistance  for  220  volts  D.  C . Duty  Free  .  .  . 


242 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PHOTOMETRIC  AND  OPTICAL  BENCHES 


PHOTOMETERS 


No.  71-10 


71-10  RITCHIE  PHOTOMETER  for  lecture  room  demonstration. 

So  little  attention  has  been  given  to  class  demonstrations  in  Photometry  that  we  believe  our  design 
will  meet  with  universal  approval.  A  photometer  head  is  provided  with  a  prism,  on  the  faces  of 
which  light  from  two  different  sources  can  fall.  A  movable  ring  with^two  uprights  which  support 
a  tilting  mirror  on  horizontal  axis  may  be  turned  in  all  directions  that  pupils  in  all  parts  of  the 
room  may  test  the  equality  of  illumination  on  both  faces  of  the  prism.  Light  shields  are  provided 
to  obstruct  rays  from  the  two  sources  of  light  striking  the  tilting  mirror. 

Complete  as  illustrated,  mounted  on  stand . . $9.75 


No.  71-20 


No.  71-30 


71-20  INVERSE  SQUARES  MODEL  for  illustrating  that  the  intensity  of  the  illumination  at  a  surface  due 
to  a  given  source  of  light  is  inversely  proportional  to  the  square  of  the  distance  of  the  surface  from 
the  source  of  light. 

The  apparatus  consists  of  a  wire  frame  constructed  as  illustrated,  with  a  maximum  axis  of  8  inches. 
Distances  from  the  source  may  readily  be  measured  and  from  the  counting  of  the  equal  squares  the 
law  may  readily  be  formulated.  This  is  a  simple  pedagogical  model  which  at  once  brings  to  the 
pupil  the  formulation  of  a  law  which  oftentimes  is  particularly  abstruse . $1.80 

71-30  CAMERA  OBSCURA,  or  PIN  HOLE  CAMERA,  for  illustrating  images  produced  through  a  small 
aperture.  This  camera  consists  of  a  rectangular  box  with  pin  hole  opening  in  front  and  a  second 
telescoping  box  with  ground  glass  plate  for  receiving  the  image . 65 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


243 


No.  71-40 

• 

71-40  LIGHT-ROOM  DIBDIN-BUNSEN  PHOTOMETER  for  determining  the  relative  intensity  of  two 
sources  of  light  without  the  necessity  of  darkening  the  room. 

This  improved  form  consists  of  a  light  proof  box  in  which  at  each  end  within  separate  compartments 
are  situated  the  sources  of  light.  Between  these  sources  slides  the  Dibdin-Bunsen  Screen,  mounted 
in  substantial  holder  connected  as  a  part  of  the  eye-shade  as  noted  in  the  illustration  and  moving 
with  it.  This  Eye-shade  and  Screen  Holder  are  fastened  at  either  end  by  narrow  opaque  spring- 
roller-bands  attached  to  the  Photometer  Box  in  such  a  manner  as  to  prevent  light  from  entering  the 
Box.  Doors  are  provided  for  access  to  either  source  of  light  or  to  the  Dibdin-Bunsen  Screen. 

Without  light  sources . ^ . $13.75 


71-50  STUDENT’S  PHOTOMETER  for  determining  by  direct  comparison  with  a  standard  the  intensity  of 
a  source  of  light. 

The  apparatus  consists  of  a  graduated  rod  at  one  end  of  which  is  attached  a  candle  holder;  at  the  other 
a  gas  tube  with  tip.  The  rod  is  mounted  on  metal  supports  as  illustrated  in  the  apparatus  of  No. 

22-160. 

The  photometer  box  with  indicator  is  fitted  with  a  Bunsen  screen,  Dibdin’s  modification,  placed  be¬ 
tween  two  mirrors  fixed  at  such  an  angle  that  both  sides  of  the  screen  can  be  viewed  simultaneously 


from  the  front. 

This  will  be  found  a  typical  student’s  instrument,  capable  of  a  fair  degree  of  accuracy.  Complete 

as  illustrated . . $3.60 

71-52  ELEMENTARY  BUNSEN  PHOTOMETER,  simple  form  complete  with  Meter  Stick,  Supports  for 
same,  Simple  Bunsen  Screen  and  Holder,  Support  for  one  and  Support  for  Four  Candles.  Com¬ 
plete  . . .  1  -00 

71-53  JOLLY  PHOTOMETER  HEAD  after  Fuller  and  Brownlee  (Experiment  37),  for  use  on  Meter  Stick  2.00 


No.  71-60 

71-80  RUMFORD’S  PHOTOMETER  for  determining  the  relative  intensity  of  two  sources  of  light. 

This  Photometer  consists  of  a  wooden  base  board  upon  which  are  mounted  two  converging  meter 
sticks.  At  the  point  of  convergence  is  mounted  a  blackened  rod,  designed  to  cast  a  shadow  on  the 
opaque  screen  held  in  the  vertical  support  as  illustrated  at  the  extreme  left  hand  side.  Two  screens 
fixed  vertically  on  either  side  of  the  rod  are  designed  for  obstruction  of  all  extraneous  light.  The 
sources  of  illumination  are  mounted  on  a  base  board,  one  on  either  side  of  the  light  shield. 

Complete  as  illustrated . . $3.60 


244 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


GENERAL  PHOTOMETRIC  OR  OPTICAL 
BENCH  ATTACHMENTS 


PHOTOMETERS 


71-100  CAST-ALUMINUM  DIBDIN-BUNSEN  PHOTOMETER  for  use  as  a  comparison  head  in  de¬ 
termining  candle  power  of  a  source  of  light.  x 

This  photometer  is  a  modification  of  the  standard  Bunsen  Screen.  In  the  Bunsen  Screen  the  trans¬ 
lucent  and  opaque  portions  do  not  transmit  light  equally.  The  grease  spot,  therefore,  even  when 
equally  illuminated,  is  never  entirely  lost.  The  Dibdin’s  modification  consists  in  exposing  a  star 
of  translucent  paper  mounted  in  heavier  paper  of  the  same  texture.  This  screen  is  mounted  be¬ 
tween  two  mirrors  at  such  an  angle  within  a  cast  metal  box  that  both  sides  of  the  screen  may  be 
seen  simultaneously.  This  cast  metal  box  is  mounted  on  a  10-millimeter  rod  for  use  with  No. 

5-810  Clamp.  It  is  blackened  inside  and  out. 

The  results  possible  with  the  Dibdin’s  modification  are  accurate  and  quickly  obtained.  We  desire 

also  to  emphasize  the  advantage  of  our  cast-metal  casing  over  the  sheet  metal  forms . $4.75 

OPTICAL  BENCH  CANDELABRUM  AND  DRIP  CUP,  for  use  with  No.  6-810  Clamp  as  a  candle 

holder  on  an  optical  bench  “built  up”  from  rods  and  clamps. 

In  the  design  of  our  Candelabrum  we  have  overcome  the  objectionable  features  of  the  various  types  on  the  mar¬ 
ket.  We  are  enabled  to  center  candles  in  groups  of  one,  two,  three,  and  four,  almost  instantly. 

This  design  consists  of  a  cast  metal  trough  mounted  on  a  rod  of  size  for  use  in  No.  6-810  Clamp.  The  Indi¬ 
vidual  Candle  Holder  is  a  casting  with  drip  cup  that  fits  into  the  trough  with  a  sliding  fit.  Any  or  all  the  Holders 
may  be  readily  moved  laterally  in  the  trough  to  properly  center  the  light. 

CANDELABRUM  TROUGH,  mounted  on  a  10-millimeter  rod,  for  use  with  No.  6-810  Clamp  .  .  $0.60 

INDIVIDUAL  CANDLE  HOLDER,  for  holding  candles . 15 

BRASS  KEROSENE  LAMP,  WICK,  AND  CHIMNEY,  for  use  on  table  top  No.  71-260  . 32 

LUMINOUS  BURNER,  especially  designed  for  use  with  No.  71-210  T.  &  H.  Light  Box  with  Wire 

Screen  . .  .45 

INCANDESCENT  LAMP  HOLDER,  mounted  on  rod  with  attachment  for  connection  to  the  stand¬ 
ard  Edison  socket. 

Without  lamp  cord  and  Edison  plug .  .95 

MOUNTED  WELSBACH  GAS  MANTLE .  1.35 

MOUNTED  CONVEX  GLASS  MIRROR.  This  is  a  convex  mirror,  3  inches  in  diameter,  focus 
6  inches,  adjustably  mounted  in  an  improved  holder  for  use  with  our  No.  6-810  Right  Angle  Clamp  2.60 
MOUNTED  CONCAVE  GLASS  MIRROR.  This  is  a  concave  mirror,  3  inches  in  diameter,  focus 

6  inches,  adjustably  mounted  in  an  improved  holder  for  use  with  our  No.  5-810  Right  Angle  Clamp  2.60 
ADJUSTABLE  PLANE  MIRROR  ON  ROD,  mirror  50  millimeters  in  diameter,  adjustable  in 
stirrup  about  a  horizontal  axis,  adjustable  on  rod  about  a  vertical  axis.  Mounted  on  nickel- 
plated  rod  15  centimeters  long,  for  use  with  our  No.  5-810  Clamp .  1.95 


71-125 

71-127 

70- 72 

71- 135 

71-140 


71-142 

71-180 

71-182 

5-960 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


245 


OPTICAL  BENCHES 


71-190  SCREEN  WITH  APERTURES.  This  is  a  metal  screen  on  which  is  mounted  a  revolving  disc  with 
apertures  of  different  sizes.  By  revolving  the  disc  these  various  sizes  of  holes  center  over  the 
large  hole  on  the  screen.  It  is  mounted  on  a  rod  ready  for  use  with  No.  5-810  Clamp . $3.30 

71-195  SCREEN  WITH  ADJUSTABLE  VERTICAL  SLIT.  This  is  a  metal  screen  with  a  two-part  metal 
slide  which  may  be  varied  at  will  to  secure  a  slit  of  any  width  up  to  one  inch.  Mounted  on  rod 
ready  for  use  with  No.  6-810  Clamp .  3.30 

71-200  SCREEN  HOLDER,  large  size,  for  holding  large  pieces  of  cardboard,  sheet  gauze,  etc .  .75 

71-205  SCREEN  HOLDER,  small  size,  for  holding  small  pieces  of  cardboard,  sheet  gauze,  etc .  .65 

71-210  T.  &  H.  BOX  WITH  WIRE  SCREEN,  for  use  in  determining  the  conjugate  foci  of  a  converging 
lens.  This  box  is  especially  designed  to  hold  a  source  of  light.  It  consists  of  a  metal  box  in  one 
face  of  which  is  a  slit  covered  by  a  wire  screen.  It  is  finished  dead  black  throughout .  .90 

71-216  EYE-SHADES,  for  use  on  a  photometer  bench  when  it  is  desired  to  shade  the  eyes  as  well  as  the  front 
of  the  screen  from  rays  from  the  sources  of  light.  They  consist  of  a  pair  of  black  cloth  shades 

suitably  mounted  for  use  with  No.  5-810  Right  Angle  Clamp . Pair  1.30 

71-225  GRADUATED  CARDBOARD  SCREEN,  10  X  10  centimeters,  for  use  with  No.  71-200  or  71-206 

Screen  Holder  .  .10 

71-227  BLACK  OPAQUE  SCREEN,  10  X  10  centimeters,  for  use  with  No.  71-200  or  71-205  Screen 

Holder  . .20 

71-230  TRANSLUCENT  OR  OPALESCENT  SCREEN,  20  X  20  centimeters,  for  use  with  No.  71-200 

Screen  Holder . .28 

71-235  CARDBOARD  METRIC  SCALES  for  use  with  No.  71-206  Screen  Holder  in  determining  the 
magnifying  power  of  a  convex  lens.  A  5-centimeter  and  a  10-centimeter  section  of  a  metric  scale 
are  mounted  on  cardboard,  the  centimeter  lines  of  one  ruled  in  red,  in  black  on  the  other.  Per  Pair  ■  .10 

5- 970  UNIVERSAL  LENS  HOLDER  for  lenses  up  to  4  inches  in  diameter.  This  ingenious  holder  is  ad¬ 

justable  by  means  of  the  rods  and  set  screws  to  hold  and  clamp  firmly,  in  or  off  center,  lenses  up 
to  4  inches  in  diameter.  Handsomely  oxidized  black  with  nickel-plated  rod.  (See  illustration, 

Section  6) .  .88 

6- 975  - ,  same  as  above,  for  holding  lenses  up  to  2  inches  in  diameter .  .78 

71-260  TABLE  TOP  ON  ROD  for  general  use  in  supporting  objects  on  optical  and  photometric  benches  1.16 

71-255  IMAGE  ON  ROD  for  use  with  No.  6-810  Right  Angle  Clamp . 65 


246 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  71-260  No.  71-260  (Sectional  View) 


71-260  LUMMER-BRODHUN  PHOTOMETER.  This  is  a  modification  of  the  grease  spot  photometer. 

Light  from  the  two  sources  falls  upon  the  screen  ik  (see  illustration),  made  of  two  sheets  of  paper 
with  tinfoil  between,  and  placed  perpendicular  to  the  direction  of  the  optical  bench.  The  diffused 
light  emitted  by  these  screens  falls  on  two  totally  reflecting  prisms  and  thence  on  to  the  faces  be 
and  dp  of  the  two  prisms  A  and  B.  The  part  rs  of  the  prism  A  which  touches  B  is  plane  so  that  all 
light  falling  on  rs  is  transmitted.  The  eye  placed  at  O  thus  receives  from  the  side  m  only  light 
which  passes  through  the  ring  rs  and  from  the  side  n  only  light  which  is  totally  reflected  from  the 
surfaces  ar  and  bs.  The  eye  thus  sees  a  bright  or  dark  spot  within  a  uniformly  bright  circle. 

When  the  photometer  is  so  adjusted  that  e  and  f  receive  the  same  amount  of  light,  the  round 
circle  of  light  entirely  disappears. 

This  photometer  box  is  mounted  in  a  frame  on  rod  designed  to  fit  our  No.  6-810  clamp  for  use  on  an 

optical  bench . Duty  Free  $36.00 


STANDARD  SOURCES  OF  LIGHT 


Nos.  71-269  and  71-270 

71-266  HEFNER  LAMP,  approved  by  the  Physikalisch-Technischen  Reichsanstalt  as  the  German  Pho¬ 
tometric  Standard  Source  of  Light,  burning  amyl-acetate.  With  flame  measure,  after  regular 

type,  wick  regulator  and  shears . .  Duty  Free  $12.60 

71r266  - ,  same  as  above,  with  certificate  of  the  Physikalisch-Technischen  Reichsanstalt  .  .  Duty  Free  16.60 

71-267  HEFNER  LAMP,  with  Flame  Measure  after  Hefner-Alteneck,  wick  regulator  and  shears.  Duty  Free  12.60 

71-268  - ,  same  as  above,  with  certificate  of  the  Physikalisch-Technischen  Reichsanstalt  .  .  Duty  Free  16.60 

71-269  HEFNER  LAMP,  with  Flame  Measure,  after  regular  type  and  also  after  Hefner-Alteneck,  wick 

regulator,  and  shears . Duty  Free  19.60 

71-270  - ,  same  as  above,  with  certificate  of  the  Physikalisch-Technischen  Reichsanstalt  .  .  Duty  Free  24.60 

71-271  AMYL-ACETATE,  C.  P.,  for  burning  in  the  Hefner  Lamp . Per  Pound  1.80 

71-272  STANDARD  CANDLE,  for  use  as  photometric  standard,  made  of  sperm,  six  to  the  pound,  will  burn 

120  grains  (7.776  grams)  per  hour . Each  .26 

Note.  No.  71-260  Table  Top  on  Rod  is  used  as  holder  for  above  sources  of  light. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


No.  98-141 


247 


Nos.  64-100  to  64-110 


No.  98-142 


98-142  MOUNTED  SELENIUM  CELL.  For  description  see  Section  98 . $14.00 

98-141  SELENIUM  CELL.  Same  as  above  but  unmounted.  For  description  see  Section  98 . 11.60 

64-100  IMPROVED  MINERALITE  THERMOPILE  “A.”  For  description  see  Section  64 . 11.76 

64-110  IMPROVED  MINERALITE  THERMOPILE  “B.”  For  description  see  Section  64 . 14.60 

6-50d  SQUARE  SUPPORT  ROD,  ungraduated,  19  millimeters  square  X  100  centimeters  long  ....  2.30 

6-60f  ,  same  as  above,  19  millimeters  square  X  200  centimeters  long .  4.46 

5- 66a  SQUARE  SUPPORT  ROD,  graduated  to  millimeters,  19  millimeters  square  X  100  centimeters  long  6.60 

6- 66b  - ,  same  as  above,  19  millimeters  square  X  200  centimeters  long . .  10.76 

6-810  RIGHT  ANGLE  CLAMP,  for  holding  two  rods  in  same  plane  but  at  right  angles  to  each  other  .  .68 

6-376  END  SUPPORTS,  especially  designed  for  holding  bed-rod  of  optical  benches.  Extreme  care  is  exer¬ 
cised  in  machining  these  supports  so  that  they  will  suit  all  requirements . Each  .66 

,  PHOTOMETRIC  AND  OPTICAL  BENCH  OUTFITS 

(Attachments  included  in  the  following  outfits  are  illustrated  on  pages  244  and  245.) 


For  the  convenience  of  those  teachers  who  desire  to  order  their  Photometric  or  Optical  Bench  Outfits  complete, 
we  list  the  following,  which  in  use  have  been  found  most  satisfactory. 

71-327  UNIVERSAL  TWO-METER  PHOTOMETRIC  OUTFIT  WITH  GRADUATED  ROD,  for  use  with 
incandescent  lamp  as  standard,  complete  as  follows: 

1  pair  End  Supports  1  Incandescent  Lamp  Holder  on  Rod 

1  Graduated  Two-Meter  Rod  1  Welsbach  Gas  Mantle  on  Rod 


1  Dibdin-Bunsen  Photometer  on  Rod  3  Right  Angle  Clamps 

Complete . $20.94 

71-327A  - ,  same  as  above,  but  with  ungraduated  rod . 14.64 

71-329  UNIVERSAL  ONE-METER  PHOTOMETRIC  OUTFIT  WITH  GRADUATED  ROD,  same  as 

No.  71-327,  but  Graduated  Rod  is  but  one  meter  long . 16.69 

71-329A  - ,  same  as  above,  but  with  ungraduated  rod . 12.49 


71-331  UNIVERSAL  TWO-METER  PHOTOMETRIC  OUTFIT  WITH  GRADUATED  ROD,  complete  as 


follows: 

1  Pair  End  Supports  1  Candelabrum  Trough  on  Rod 

1  Graduated  Two-Meter  Rod  4  Individual  Candle  Holders 

1  Dibdin-Bunsen  Photometer  on  Rod  1  Incandescent  Lamp  Holder  on  Rod 

1  Pair  Eye-Shades  5  Right  Angle  Clamps 

Complete  . 23.46 

71-331A  - ,  same  as  above,  but  with  ungraduated  rod . 17.16 

71-332  UNIVERSAL  ONE-METER  PHOTOMETRIC  OUTFIT  WITH  GRADUATED  ROD,  same  as  No. 

71-331,  bqt  Graduated  Rod  is  but  one  meter  long . 19.20 

71-332A  - ,  same  as  above,  but  with  ungraduated  rod . 16.00 


OPTICAL  BENCHES 

The  above  outfits,  with  the  additions  of  a  few  attachments  found  on  pages  244  and  245,  will  constitute  excellent 
optical  benches. 

We  recommend  the  following  additions  to  any  of  the  above  outfits. 

71-340  OPTICAL  BENCH  ATTACHMENTS,  consisting  of  Screen  Holder,  Graduated  Opaque  Screen, 

Black  Opaque  Screen,  Translucent  Screen,  Image  on  Rod  and  Lens  Holder  for  lenses  up  to  4 
inches  in  diameter . $3.66 

Lenses,  Section  74.  Prisms,  Section  74.  Mirrors,  Section  72.  Candles,  Section  70. 


248 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


• » 


71-350  STUDENTS’  OPTICAL  BENCH,  a  simple  outfit  for  optical  experiments  by  students.  The  apparatus 
is  shipped  complete  with  meter  stick,  a  lens  holder,  one  lens  with  finished  edges,  inches  diam¬ 
eter,  15  centimeters  focus,  a  pin  holder,  pair  of  metal  supports  for  meter  stick,  screen  holder,  and 
cardboard  screen .  . .  $1.10 


SIMPLE  PHOTOMETRIC  AND  OPTICAL  ATTACHMENTS 


11-10  METER  STICK . $0.28 

71-352  LENS  HOLDER . 11 

74-121  LENS,  1J4  inches  diameter,  6  inches  focus . 24 

22-160b  METAL  SUPPORTS  FOR  METER  STICK . Per  Pair  .25 

71-356  SCREEN  HOLDER . 08 

71-225  GRADUATED  CARDBOARD  SCREEN . 10 

71-358  PIN  HOLDER . 08 

71-376  BLOCK  AND  BENT  WIRE  for  finding  real  and  virtual  images  in  a  lens. 

This  is  the  standard  piece  so  frequently  called  for  in  the  many  manuals  in  use  among  secondary 

schools  .  .20 

71-376  WIRE  BENT  AT  RIGHT  ANGLES  after  Hall,  No.  73 . 02 

71-360  MOUNTED  CARDBOARD  SCREEN . 28 

71-362  OPAQUE  SCREEN  WITH  CROSSED  OPALESCENT  SQUARE  OPENING,  after  Fuller  and 

Brownlee  (Experiment  40) .  .30 

71-364  BLACK  AND  WHITE  OPAQUE  SCREEN  WITH  SQUARE  OPENING,  after  Fuller  and  Brown¬ 
lee  (Experiment  48) .  .20 

71-366  BUNSEN  SCREEN,  simple  form  for  use  in  Holders  Nos.  71-356  and  71-368  . 10 

71-368  SCREEN  HOLDER  for  use  on  meter  stick,  after  Turner  and  Hersey  (Experiment  L011) .  .60 

71-370  CANDLE  HOLDER  FOR  ONE  CANDLE,  for  use  on  meter  stick,  after  Turner  and  Hersey  (Ex¬ 
periment  L011) .  .30 

71-372  - ,  for  FOUR  CANDLES  for  use  on  meter  stick,  after  Turner  and  Hersey  (Experiment  L011)  .  .40 

71-380  CARDBOARD  DIAPHRAGM  WITH  ONE  CENTIMETER  OPENING,  after  Turner  and  Hersey 

(Experiments  L101  and  L105)  .06 

71-400  CULLER’S  PRINCIPLE  FOCUS  BOX,  after  Culler  (Experiment  XXXV)  .  1.26 

71-600  MOUNTED  CONVEX  LENS  AND  WIRE  SCREEN,  after  Millikan,  Gale  and  Bishop  (Experiment 

46) . 76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


249 


REFLECTION  OF  LIGHT 

MIRRORS 


'  Nos.  72-10  to  72-45 

72-10  PLANE  GLASS  MIRROR  for  experiments  in  reflection  of  light.  Best  German  glass,  6  inches  long 

by  2  inches  wide . Each  $0.08 


72-10a  SPRING  BRASS  CLIPS  for  holding  mirror  to  a  block . Pair  .30 

72-10b  VERTICAL  INDEX  BLOCK  with  white  face,  after  Hall,  No.  66 . 15 


72-12  PLANE  MIRROR,  similar  to  No.  72-10,  but  6  inches  X  4  inches . Each  .16 

72-15  BLACKENED  PLATE  OF  GLASS,  after  Millikan,  Gale  and  Bishop  (Experiment  42) .  .06 


72-20  CONCAVE  AND  CONVEX  CYLINDRICAL  MIRROR.  This  is  a  cylindrical  brass  mirror,  carefully 

burnished  on  both  sides  and  heavily  nickel-plated.  One  side  is  concave  and  the  other  convex.  Each  .60 


72-20a  BRASS  PLATE  with  four  Projecting  Needles,  after  Hall,  No.  67a .  .75 

!  72-20b  BRASS  PLATE  with  seven  Projecting  Needles,  after  Hall,  No.  67b .  1.25 


1  72-26  CONCAVE  AND  CONVEX  SPHERICAL  MIRROR.  This  is  a  spherical  mirror  of  brass,  3  inches 
in  diameter,  6-inch  focus.  It  is  carefully  burnished  and  nickel-plated  on  each  side,  one  side  convex 


and  the  other  concave  .  .50 

72-35  CONVEX  MIRROR.  This  is  a  carefully  silvered  glass  mirror  with  a  protective  coating.  It  is  3 

inches  in  diameter,  with  a  focus  of  6  inches .  1.25 

72-37  CONCAVE  MIRROR.  This  is  a  carefully  silvered  glass  mirror  with  a  protective  coating.  It  is 

3  inches  in  diameter,  with  a  focus  of  6  inches .  1.25 

72-45  MOUNTED  CONCAVE  AND  CONVEX  MIRROR.  This  instrument  consists  of  two  mirrors,  one 

concave,  the  other  convex,  mounted  in  a  circular  wooden  frame,  with  handle;  diameter  5  inches  .  .  2.25 


250 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


\ 


No.  72-70 


No.  72-60 


72-60  IMPROVED  INCIDENCE  AND  REFLECTION  APPARATUS  for  determining  the  law  of  reflection 

of  light. 

In  use,  one  arm  is  set  at  any  desired  position.  Sighting  across  the  second,  this  arm  is  moved  until 
the  image  of  the  first  and  the  etched  line  of  the  mirror  and  the  sighting  edge  of  the  second  are  in 
the  same  straight  line.  If  the  positions  of  these  index  arms  are  noted  on  the  graduated  arc  it  will 
be  found  that  the  Angle  of  Incidence  is  equal  to  the  Angle  of  Reflection . $2.25 

72-70  GAGE’S  REFLECTION  APPARATUS  for  demonstrating  the  law  of  reflection  of  light. 

By  glancing  in  the  mirror  through  the  hole  marked  “O”  an  image  only  of  the  hole  is  seen.  If  the 
source  of  light  is  held  before  any  of  the  other  holes  the  image  in  the  mirror  can  be  seen  only  through 
the  hole  equally  distant  on  the  other  side  of  the  normal  to  the  mirror . .  2.45 

22-146  INCIDENCE  AND  REFLECTION  APPARATUS.  The  apparatus  illustrated  consists  of  an  attach¬ 
ment  for  our  Universal  Stand  No.  22-130. 

In  use,  the  candle  is  placed  in  the  holder  and  trimmed  so  that  its  flame  may  be  on  the  plane  with 
the  sight  hole.  It  is  then  lighted.  The  arm  for  carrying  the  sight  hole  is  moved  along  until  the 
rays  of  the  candle  flame  are  seen  through  the  sight  hole.  By  a  glance  at  the  sector  line  it  will  be 
found  that  this  Line  of  Reflection  makes  the  same  angle  with  the  normal  to  mirror  as  the  Line  of 
Incidence  makes  with  this  perpendicular,  thus  proving  that  the  Angle  of  Reflection  is  equal  to 
the  Angle  of  Incidence .  6.66 


No.  72-90  No.  72-96 

72-90  MULTIPLE  REFLECTION  APPARATUS  for  illustrating  the  phenomenon  of  multiple  reflection. 

This  apparatus  consists  of  a  handsomely  finished  metal  casting  on  which  arc  degree  lines  denoting 
every  ten  degrees.  Two  mirrors,  mounted  on  appropriate  metal  frames  and  hinged  at  the  center 
of  the  circle,  are  movable  within  180°.  In  this  casting  a  candle  holder  is  provided  for  holding  the 
candle  in  the  best  possible  position.  A  further  advantage  of  this  model  is  that  the  mirrors  may  be 
unhinged  from  the  center  and  mounted  parallel,  thus  showing  the  infinite  number  of  images  that 
may  be  formed  in  mirrors  mounted  parallel  to  each  other . $6.60 

72-96  PLACED  IMAGE  MULTIPLE  IMAGE  APPARATUS,  after  Hall  and  Bergen’s  “A  Text-Book  of 

Physics,”  page  158. 

In  use  the  mirrors  are  placed  upon  the  board  with  the  reflecting  surfaces  making  an  angle  of  90°,  —  in 
the  position  as  illustrated.  The  lighted  candle  should  be  of  such  height  that  its  flame  will  not  be 
above  the  upper  edge  of  the  mirrors  and  should  be  exactly  over  the  middle  hole  in  front  of  the  board. 

The  positions  of  the  images  of  the  candle  should  now  be  noted  and  pegs  placed  into  the  holes  be¬ 
hind  the  mirrors  in  such  a  position  that,  to  an  observer  placed  in  front  of  tne  mirrors,  the  images  in 
the  mirrors  and  the  pegs  over  the  mirror  will  appear  to  coincide  with  the  images.  The  experiment 
should  be  modified  with  the  mirrors  at  angles  of  60°  and  30°  also .  2.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


251 


No.  72-100 


72-100  KALEIDOSCOPE.  This  apparatus  is  a  design  of  our  own  and  consists  of  3  mirrors,  each  separately 
mounted  in  a  metal  frame  and  combined  to  form  a  case  with  mirrors  at  angles  of  60°.  One  end 
is  closed  by  a  disc  of  ground  glass,  the  other  is  provided  with  a  cap  with  an  aperture.  Fragments 
of  colored  glass  are  placed  at  one  end  between  the  ground  glass  discs  and  the  second  clear  glass  disc. 

The  objects  and  their  images  when  viewed  through  the  aperture  present  themselves  in  an  endless 
variety  of  symmetrical  forms  as  the  Kaleidoscope  tube  is  turned . $2.76 


72-106  STUDENTS’  KALEIDOSCOPE,  similar  in  design  to  above,  but  of  simpler  construction . 48 


No.  72-126  No.  72-140 

72-125  LUMINOUS  CASCADE,  used  with  a  strong  source  of  light  and  a  condenser  for  showing  total  reflec¬ 
tion  by  means  of  a  jet  of  water.  The  cylindrical  vessel  illustrated  is  placed  in  front  of  the  source 
of  light  in  such  a  way  that  the  glass  disc  is  parallel  to,  and  about  2  centimeters  from,  the  con¬ 
denser.  Water  as  pure  as  possible  is  poured  into  the  vessel  and  allowed  to  issue  from  the  jet 
orifice.  The  stream  of  water  is  then  seen  to  be  illuminated  for  a  considerable  distance. 

A  pleasing  modification  of  this  experiment  is  to  insert  colored  glass  plates  between  the  condenser 

and  the  window  of  the  vessel . $6.40 


72-140  OPTICAL  DISC  TOTAL  REFLECTION  APPARATUS  for  showing  total  reflection  in  glass  rods; 
also  illustrating  the  Luminous  Cascade. 

The  apparatus  consists  of  a  dull  black  board  designed  for  attachment  to  the  face  of  the  Optical  Disc 
as  illustrated.  On  the  board  are  mounted  three  bent  glass  rods,  one  of  which  is  smooth,  the  other 
two  covered  with  small  chinks  of  glass.  The  ends  of  these  rods  pass  through  a  diaphragm  on  which 
the  light  falls.  Light,  therefore,  enters  these  rods  through  the  ends.  The  effect  is  readily  notice¬ 
able.  The  smooth  rod  remains  dark,  while  the  ones  with  small  chinks  glisten  with  bright  light. 

The  light,  however,  in  the  smooth  rod,  being  conveyed  further  by  total  reflection,  passes  out  in 
nearly  full  strength  upon  a  screen  mounted  to  the  face  of  the  board;  on  the  other  hand,  the  spot 
of  light  received  on  the  screen  from  the  rod  with  small  chinks  is  noticeably  fainter,  inasmuch  as  the 
light  in  the  rod  has  partially  passed  out  through  the  chinks  in  the  walls  causing  the  glistening 
bright  light. 

This  experiment  is  extremely  effective  when  colored  light  is  used.  It  has  distinct  advantages  over 
the  Luminous  Cascade  No.  72-126,  in  that  the  observations  of  the  experimenter  are  not  disturbed 
by  the  necessity  of  catching  the  water  and  refilling  the  apparatus. 

Complete  ready  for  attachment  to  face  of  Optical  Disc . Duty  Free  .  .  . 


252 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


KOLBE-HARCOURT  SELF-CONTAINED 


UNIVERSAL  INCLINATION  OPTICAL 

DISC 

No.  73-10 


Front  View 
Dial  Tilted 


The  Optical  Disc  is  doubtless  the  most  satisfactory  outfit  ever  designed  for  illustrating  in  simple  and  concise 
form  the  fundamental  laws  of  optics. 

Rays  of  sunlight,  direct  or  reflected,  will  show  as  white  paths  of  light  across  the  face  of  the  dial.  When  a  prism, 
lens  or  mirror  is  placed  in  these  paths,  the  light  is  refracted  or  reflected  as  may  be  noticed  from  the  paths  traced  by 
the  rays  of  light.  Results  are  clear  and  positive.  They  can  be  viewed  by  the  whole  class  even  across  a  large  lecture 
room. 

A  great  many  instructive  experiments  may  be  demonstrated  and  the  phenomena  studied  by  the  entire  class.  In 
a  special  pamphlet  which  we  will  send  on  application,  we  have  suggested  a  few  of  these  that  can  be  considered  as 
fundamental.  Experience  will  suggest  many  others.  This  instrument  has  been  designed  particularly  for  use  in  a 
lecture  hall.  Our  new  model,  the  Kolbe-Harcourt  Optical  Disc,  retains  the  same  optical  perfection  of  our  original 
design,  yet  the  following  mechanical  characteristics  greatly  enhance  its  value  and  will  readily  serve  to  distinguish 
our  instrument. 


FEATURES 

1.  The  apparatus  is  self-contained  in  that  prisms,  lenses,  mirrors,  etc.,  are  provided  for  on  the  in¬ 
strument  itself. 

2.  Any  conceivable  angle  of  tilt  for  the  dial. 

3.  Shade  and  dial  are  independently  mounted  on  separate  axes  and  may  be  rotated  independently  of 
each  other. 

4.  Greater  stability  secured  by  our  rectangular  metal  base  with  forked  upright  support. 

5.  The  recessed  portion  with  individual  pockets  for  each  optical  part  enables  one  to  definitely  locate 
any  of  the  parts  when  operating  in  a  dark  room. 

6.  The  instrument  is  scientific  in  structure  and  appearance. 

7.  A  13-inch  dial  with  improved  graduations  distinctly  and  clearly  brought  out  by  careful  differen¬ 
tiation  of  lines  and  figures. 


PRICE,  $16.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


253 


A  ray  reflected  from  a  plane 
mirror.  Angle  of  incidence  equal 
to  angle  of  reflection. 


Reflection  from  a  concave 
mirror.  Showing  convergence 
of  rays. 


Reflection  from  a  plane  mirror. 
Incident  parallel  rays  are  re¬ 
flected  parallel. 


One-half  of  ray  refracted. 
Showing  angle  of  refraction. 


Total  reflection.  Showing 
rays  totally  reflected  at  the  hy- 
pothenuse  and  reversed  upon 
emerging. 


Refraction  through  double 
convex  lens.  Showing  con¬ 
vergence  of  rays. 


Ray  partly  reflected,  partly 
refracted.  Showing  angle  of  in¬ 
cidence  and  refraction. 


Refraction  through  double 
concave  lens.  Showing  diver¬ 
gence  of  rays. 


Reflection  from  a  convex  mir¬ 
ror.  Showing  divergence  of 
rays. 


Angle  of  deviation  —  mini¬ 
mum  angle  of  deviation.  Show¬ 
ing  an  incident  ray  emerging 
parallel,  since  surfaces  are  par¬ 
allel. 


Ray  totally  reflected.  By 
turning  disc,  critical  angle  may 
be  determined. 


Send  for  Special  Pamphlet  describing  experiments  suggested  above  in  diagram. 


254 


KNOTT  APPARATUS  CO.,  BOSTON 


73-60  DIVERGING  RAY  ATTACHMENT.  This  attachment  consists  of  a  system 
of  concavo-cylindrical  lenses  mounted  in  a  frame  and  adjustably  supported 
in  a  clamp  on  a  tripod  stand. 

In  use  the  concavo-cylindrical  surfaces  are  directed  toward  the  light  source. 

Each  individual  lens  sends  out  a  bundle  of  diverging  rays  and  one  ray  from 
each  lens  will  pass  through  the  slit  in  the  screen,  forming  a  system  of  diverg¬ 
ing  rays  which  appear  to  come  from  the  slit  as  a  source  and  cross  the  face  of 
the  dial. 

Many  of  the  experiments  described  under  the  Kolbe-Harcourt  Optical  Disc 
should  be  repeated,  using  the  diverging  rays.  Better  educational  results  are 
secured  if  diverging  rays  through  but  two  slits  are  used  and  the  light  through 
one  of  these  slits  be  made  to  pass  through  a  colored  strip  of  glass  placed 
under  the  clips  provided  on  the  screen  for  the  purpose.  This  arrangement 
enables  one  to  definitely  locate  the  different  foci  and  to  trace  the  formation 
of  real  and  virtual  images. 

Diverging  Ray  Attachment  complete  as  illustrated . $6.60 


73-76 


No.  73-60 


No.  73-76 


REFRACTION  TANK  for  study  of  refractions  in  water  and  for 
determining  the  index  of  refraction  of  any  liquid  inactive  upon 
the  metal. 

This  attachment,  which  fastens  to  the  center  of  the  Kolbe  Optical 
Disc,  consists  of  a  circular  tank  with  glass  front.  This  glass 
covers  slightly  more  than  one-half  circle  so  that  the  water  level 
may  be  used  at  the  90-90  mark.  That  results  may  be  quanti¬ 
tatively  made  the  whole-circle  back  is  graduated. 

In  use  the  tank  is  attached  to  the  face  of  the  disc  and  filled  to  the  90-90  degree  line 
with  the  liquid  to  be  studied.  A  ray  of  light  is  then  allowed  to  strike  the  surface  of 
the  liquid.  This  ray  traces  a  path  through  the  liquid  which  may  be  read  through  it. 
From  the  Angle  of  Incidence  read  from  the  face  of  the  disc  and  Angle  of  Refraction 
read  from  the  graduated  circular  back  the  Index  of  Refraction  of  the  Liquid  may  be 
determined. 

Refraction  Tank  ready  for  use  on  disc . 


$3.36 


No.  73-80 

73-80  POLARIZED  LIGHT  ATTACHMENT.  This  device  is  used  in  studying  the  fundamental  phenomena 
of  Polarized  Light,  —  uniform  reflection  of  ordinary  unpolarized  light,  polarization  by  reflection, 
polarization  by  multiple  refractions,  chromatic  polarization  and  many  other  important  phenomena 
that  readily  suggest  themselves  when  the  instrument  is  in  use. 

All  parts  of  this  attachment  are  fastened  to  a  rectangular  metal  plate  which,  in  use,  is  held  to  the  face 
of  the  disc  by  means  of  thumb  screws.  At  one  end  of  the  rectangular  metal  plate  will  be  found  the 
holder  for  the  polarizers,  —  the  single  plate  of  glass  and  the  bundle  of  glass  plates;  at  the  other  end  is 
the  analyzer,  —  a  heavy  black  glass  plate  held  at  proper  inclination  and  position  in  a  special  holder 
which  permits  of  rotary  motion.  To  this  same  holder  is  attached  the  projection  screen  in  rotary  ad¬ 
justment.  Between  analyzer  and  polarizer  is  situated  the  stage  provided  with  a  simple  holder  for 
specimens  for  study  under  polarized  light. 

The  attachment  is  fastened  to  the  dial  of  the  Kolbe-Harcourt  Optical  Disc  in  the  same  manner  as  are 
the  various  optical  parts  in  previous  experiments,  short  thumb  screws  provided  with  the  attachment 
being  used  for  this  purpose.  Use  the  full  beam  of  light  through  the  rectangular  opening  in  the  shade 


$8.26 


73-90  THE  COWEN  N.  and  F.  APPARATUS  for  use  on  Optical  Disc  to  illustrate  near  and  far  sightedness  1.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


255 


No.  73-101 

HARCOURT  IMPROVED  STUDENTS’ 

OPTICAL  DISC 


The  Kolbe-Harcourt  Optical  Disc  previously  illustrated  and  described,  was  designed  and  especially  constructed 
with  universal  adjustment  for  use  in  lecture  work.  No.  73-101,  above  illustrated,  is  a  simplified  form  utilizing  the 
same  optical  parts  but  for  use  in  horizontal  position  only.  The  design  is  particularly  adapted  to  experiments  de¬ 
scribed  in  our  National  Physics  Direction  Sheets  Nos.  L110  to  L118,  a  full  list  of  these  experiments  being  supplied 
with  each  outfit. 

Illustrated  above  and  in  our  National  Physics  Direction  Sheets  Nos.  L110  to  L118  will  be  noted  our  Incan¬ 
descent  Lamp  and  Shield.  This  apparatus  has  been  found,  a  most  convenient  and  satisfactory  source  of  light. 

Direction  sheets  are  furnished  and  the  Students’  Optical  Disc  is  particularly  adapted  to  following  experiments: — 

1.  With  Plane  Mirror,  —  Law  of  Reflection;  Parallel  Rays;  Diverging  Rays;  Image  of  a  Point. 

2.  With  Concave  Mirror,  —  Normal  Incidence;  Principal  Focus;  Parallel  Beam  by  Reflection;  Spherical 
Aberration;  Caustic  Curve. 

3.  With  Convex  Mirror,  —  Parallel  Rays;  Principal  Focus;  Virtual  Image  of  a  Point. 

4.  With  Trapezoidal  Glass  Plate,  —  Lateral  Aberration;  Path  of  Ray  through  Prism;  Minimum  Devia¬ 
tion;  Disperson. 

5.  With  45  Degree  Right  Prism,  —  Single  and  Double  Total  Internal  Reflection. 

6.  With  Convex  Lens  —  Ray  through  Optical  Center;  Principal  Focus;  Spherical  Aberration;  Conju¬ 
gate  Foci. 

7.  With  Concave  Lens,  —  Ray  through  Optical  Center;  Principal  Focus. 

8.  With  Semi-circular  Glass  Plate,  —  Ray  passing  between  Glass  and  Air;  Index  of  Refraction  for  Glass; 

Critical  Angle;  Total  Internal  Reflection. 

HARCOURT  IMPROVED  STUDENTS’  OPTICAL  DISC  without  Optical  Parts . $8.76 

73-102  OPTICAL  DISC  GLASS  PARTS,  complete  as  described  under  No.  73-101 .  6.26 

Note.  One  set  No.  73-102  will  be  found  sufficient  for  four  groups  of  pupils. 

73-106  SPECIAL  110-VOLT  LIGHT  BOX,  designed  by  C.  Brooks  Hersey  of  the  Masten  Park  High  School, 
Buffalo,  New  York,  for  general  laboratory  work 


3.26 


7 


255  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


REFRACTION  OF  LIGHT 


Nos.  74-50  to  74-62 


74-60  INDEX  OF  REFRACTION  PLATE,  GILLEY  FORM,  for  determining  the  index  of  refraction  of  glass. 
This  is  a  standard  glass  index  of  refraction  plate,  universally  described  in  text-books  and  manuals. 
Dimensions,  3X4  inches.  Polished  edges . 

74-56  EQUILATERAL  PRISM,  after  Millikan  and  Gale’s  “A  Laboratory  Course  in  Physics”  (Experiment 
43).  This  is  a  triangular  prism  of  heavy  glass  plate,  75-millimeter  edge.  Edges  polished  .  .  .  . 

74-60  GLASS  CUBE  for  the  determination  of  the  index  of  refraction  of  glass.  Polished  faces,  30-milli¬ 
meter  edge . 

74-62  -  — ,  same  as  above,  but  50-millimeter  edge . 


No.  74-76  No.  74-65 


74-76  GILLEY  INDEX  OF  REFRACTION  OF  WATER  BOARD  for  determining  the  index  of  refraction  of 

water. 

This  apparatus  consists  of  a  thin  board  attached  to  a  cross-head.  The  cross-head  is  of  the  size  and 
length  to  hold  the  board  perpendicular  in  the  jar  of  water.  The  line  of  sight  as  well  as  the  water 
level  is  determined  by  means  of  pins.  Without  Jar . 

31-265c  GLASS  JAR  for  above,  6X8  inches . 

74-81  BRASS  PARTITION  with  attached  clamps  according  to  Hall  and  Bergen . 

74-82  BRASS  CLAMPS  with  index  points  according  to  Hall  and  Bergen . Each 

74-85  ADJUSTABLE  SIGHTING  ARM  INDEX  OF  REFRACTION  OF  WATER  APPARATUS,  a  greatly 

improved  design  according  to  Culler’s  “Laboratory  Manual  of  Physics”  (Experiment  XXXIV).  Can 
be  clamped  on  any  jar,  square  or  round,  —  an  important  feature  in  that  the  angle  of  refraction 
may  be  accurately  transferred  to  the  note-book  page  by  removing  the  apparatus  from  jar  and 
pressing  needle  points  down  into  the  blank  sheet.  Without  jar . 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


257 


No.  74-90  No.  74-92 

74-90  PRATT  INSTITUTE  INDEX  OF  REFRACTION  APPARATUS  for  determination  of  Index  of  Re¬ 
fraction  of  Water. 

This  instrument  consists  of  a  metal  casting  holding  a  metal  strip  with  spring  grip  in  each  of  the  four 
slots.  The  lower  ends  of  the  two  inner  strips  are  intended  to  give  the  line  of  water,  the  strip  at  right 
of  the  illustration  to  give  the  angle  of  incidence.  In  use  the  lower  end  of  this  strip  touches  the 
water  line,  the  line  of  sight  starting  over  the  beveled  top.  The  fourth  strip  is  adjusted  to  give  the 
line  of  refraction.  Beginning  with  the  strip  at  the  left,  then,  the  line  of  sight  is  over  the  top  of  the 
first  across  the  bottom  of  the  second  to  the  bottom  of  the  fourth.  When  these  points  are  obtained 
the  instrument  is  taken  from  the  jar  and  the  straight  edges  placed  on  a  sheet  of  paper  and  the  line 
of  sight  drawn.  Index  may  be  determined  by  ordinary  geometrical  method  or  the  sines  of  the  angles 
obtained  may  be  secured  from  any  logarithmic  table. 

The  simplicity  of  this  instrument  will  appeal  to  all.  The  facility  of  use,  scientific  observation  of  de¬ 
tails  and  appearance  will  doubtless  be  noted.  Without  jar . $2.10 

74-92  UNIVERSAL  DIRECT  READING  INDEX  OF  REFRACTION  APPARATUS  for  determining  the 
index  of  refraction  of  any  colorless  liquid,  —  acid  or  alkali. 

This  instrument  consists  of  a  base  on  which  is  mounted  a  graduated  rod.  On  this  rod  is  fitted  a  frame, 
free  to  move  up  and  down  the  rod,  and  which  may  be  clamped  wherever  desired  by  means  of  set 
screws.  To  this  frame  are  attached  an  arc  and  a  side  tube  with  cross-wire.  This  side  tube  is  swiv¬ 
eled  at  the  center  of  the  arc.  A  clear  glass  jar  is  held  to  the  base,  close  up  to  the  frame,  by  means 
of  spring  clips  fastened  to  the  base.  The  side  nearest  the  arc  has  engraved  on  its  face  four  lines. 

The  opposite  side  is  provided  with  a  metal  frame  on  which  slides  a  screen  with  movable  slit.  The 
line  of  sight,  therefore,  is  from  the  cross-wire  inside  of  the  tube  through  the  tube  through  one  of 
the  lines  engraved  on  the  jar  to  the  slit  on  the  opposite  side  of  the  jar. 

The  apparatus  is  accurately  constructed,  graduations  clear  and  distinct,  handsomely  finished. 

Three  methods  of  determining  the  index  of  refraction  of  a  liquid  are  possible : 

1.  Index  of  Refraction  may  be  read  from  the  arc,  and  the  sines  of  the  angles  from  any 

logarithm  table. 

2.  Length  of  the  sines  may  be  read  directly  by  means  of  the  sliding  index  on  the  graduated 

rod. 

3.  The  index  may  be  determined  by  the  usual  geometrical  construction  of  the  angles  to  the 

mensuration  of  the  sines. 

Apparatus  complete  as  illustrated,  furnished  with  simple  laboratory  directions . 4.30 

74-96  REFRACTION  TANK  for  experiments  on  refraction  at  plane  surfaces. 

This  tank  consists  of  a  semi-circular  vessel  of  glass,  one  side 
of  which  is  curved,  and  the  other  side  opaque  except  for 
the  slit  through  which  the  light  may  enter  the  tank.  The 
reading  of  the  path  of  the  light  may  be  made  when  the 
tank  is  empty. 

This  is  an  interesting  and  instructive  experiment  and  the 
apparatus  is  sufficient  in  size  for  use  in  lecture  experi¬ 
ments  . '  .  .  .  $8.00 


No.  74-96 


258 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


DEMONSTRATION  LENSES 


Used  by  express  permission  of  copyright  owner 

No.  74-107 


74-107  DEMONSTRATION  LENSES.  A  set  of  10  lenses,  each  3  inches  in  diameter. 

These  lenses  include  one  each  of  the  following  types: 

Double-convex,  double-concave  Cylindrical-convex,  cylindrical-concave 

Plano-convex,  plano-concave  Sphero-cylindrical,  sphero-prismatic 

Periscopic  convex,  periscopic  concave 

The  complete  set  of  10  lenses,  3  inches  in  diameter . $12.60 


74-110  DEMONSTRATION  LENSES.  Set  including  one  each  of  the  following  lenses: 

Double-convex,  double-concave  Plano-convex,  plano-concave 
Periscopic  convex,  periscopic  concave 

Set  of  6  lenses,  2  inches  in  diameter,  in  box .  2.50 

74-112  - ,  set  of  6  lenses,  same  as  above,  IK  inches  in  diameter,  enclosed  in  cardboard  box  .  1.26 


LABORATORY  LENSES 


DOUBLE  CONVEX  LENSES,  highest  quality,  carefully  polished,  ground  edges. 


Number  .  . 

.  74-118 

74-120 

74-121 

74-122 

74-122a 

74-123 

74-124 

74-125 

74-126 

Diameter  .  . 

•  IK 

IK 

IK 

2 

2 

2  K 

3 

4 

4  inches 

Focus  .  .  . 

.  2 

4 

6 

5 

20 

6 

7 

10 

16  inches 

Each  .  .  . 

.  $0.60 

.27 

.24 

.42 

.36 

.60 

.76 

.95 

1.30 

DOUBLE  CONCAVE  LENSES,  highest  quality,  carefully  polished,  ground  edges. 


Number  .  .  . 

74-160 

74-161 

74-162 

Diameter  .  .  . 

IK 

IK 

2 

Focus  .... 

6 

8 

8 

Each  .... 

.22 

.22 

.60 

74-163 

3  inches 
6  inches 

.90 


CONDENSING  LENSES,  plano-convex,  highest  quality,  carefully  polished,  ground  edges. 
Number  .  .  .  74-170  74-171  74-172 

Diameter  .  .  .  4J4  4K  5 

Focus  ....  6^  10  8 

Each  ....  $1.10  '  1.10  1.70 


74-173 

6  inches 
10  inches 

6.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


259 


MISCELLANEOUS  LENSES 


No.  74-190  No.  74-230  Nos.  74-220  to  74r-225 


74-180  WATER  LENS.  This  is  a  hollow  plano-convex  vessel,  with  opening  for  introduction  of  water. 

Diameter  80  millimeters . 

74-182  WATER  LENS.  This  is  a  hollow  double-convex  vessel,  with  opening  for  introduction  of  water. 

Diameter  80  millimeters . 

74-190  DEMONSTRATION  ACHROMATIC  LENS.  This  lens,  in  reality,  consists  of  2  lenses,  a  concave 
and  a  convex  lens,  each  1 Y2  inches  in  diameter,  accurately  ground  to  fit  each  other.  Achromatism 

positive .  Per  Pair 

74-192  ACHROMATIC  LENS,  consisting  of  two  lenses,  a  diverging  concavo-convex  flint  glass  lens  and  a 
double-convex  crown  glass  lens,  accurately  ground  and  polished,  and  perfectly  fitted  to  each 

other.  Diameter  2  inches,  focus  8  inches . 

74-210  MOUNTED  CONDENSING  LENS.  This  is  a  condensing  lens  5-inch  diameter,  8-inch  focus,  mount¬ 
ed  on  the  Hall  Universal  Stand,  adjustable  to  height  and  plane.  The  stand  is  of  brass  and  of  a 
design  constructed  to  facilitate  in  obtaining  all  positions  desired  for  the  lens  in  laboratory  prac¬ 
tice.  Brass  parts  are  polished  and  lacquered;  base  is  finished  in  black  japan. 

Complete  as  illustrated . 

74-215  MOUNTED  DOUBLE-CONVEX  LENS.  This  is  a  double-convex  lens,  4-inch  diameter,  14-inch  focus, 

mounted  in  a  universally  adjustable  stand  described  under  No.  74-210 . 

74-220  MOUNTED  HOLLOW  PLANO-CONVEX  LENS.  This  is  an  80  mm.  plano-convex  water  lens, 

mounted  as  illustrated . !  .  .  .  . 

74^-226  MOUNTED  HOLLOW  DOUBLE-CONVEX  LENS.  This  is  an  80  mm.  double-convex  water  lens, 

mounted  as  illustrated  above . 

74r-230  READING  LENS.  This  is  a  double-convex  lens,  mounted  in  a  metal  frame  and  provided  with 
handle.  Diameter  of  lens  3  inches . 


$3.90 

3.90 


.75 


4.80 


5.65 

5.25 

5.25 

5.25 

1.00 


74-231  LONG  FOCUS  LENS  with  handle . 60 

74-236  POCKET  MAGNIFIER  (LINEN  TESTER).  This  is  a  small  double-convex  lens,  short  focus, 

J/ £-inch  aperture.  It  is  mounted  in  a  brass  piece  that  may  be  folded  into  small  compass  ....  .44 


74-240  KUEHNE’S  EYE  MODEL  for  the  demonstration 
and  study  of  the  optical  construction  of  the  eye, 
its  normal  and  abnormal  condition  and  the  neces¬ 
sary  corrections. 

The  apparatus  consists  of  a  water-tight  rectangular 
box  with  various  accessories,  such  as  the  two  cor¬ 
neas,  one  of  which  is  fitted  with  a  cylindrical  lens, 
two  eye  lenses  of  different  foci,  three  diaphragms, 
retina  and  six  glasses  to  be  used  in  front  for  cor¬ 
recting  errors. 

Apparatus  complete  as  above  described,  including 

full  instructions  for  use . . $28.00 

74-247  MODEL  OF  HUMAN  EYE  of  plaster  of  paris.  Dis- 

sectible  . ' .  6.60  No.  74-240 


26o 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


LABORATORY  PRISMS 


Used  by  express  permission  of  copyright  owner 


Nos. 


74-295  74-297  74-280 

74-282 

74-305 

74-316  74-285 

74-307 

74-275 

74-287 

74-276  STUDENTS’  ODD  ANGLE  GLASS  PRISMS  for  general  laboratory  use,  particularly  for  deter¬ 
mining  the  index  of  refraction. 

The  tendency  of  pupils  to  copy  results  has  led  to  the  demand  for  prisms  with  odd  angles.  This  set 
is  one  that  has  found  favor  in  the  laboratories  of  Cornell  University  and  we  have  no  hesitancy  in 
recommending  its  use  in  any  laboratory.  The  set  consists  of  six  prisms  about  1  inch  high  and 
1  inch  face,  with  the  following  angles:  first  prism,  55°,  65°,  and  60°;  second  prism,  48°,  69°,  and 
63°;  third  prism,  54°,  67°,  and  59°;  fourth  prism,  42°,  74°,  and  64°;  fifth  prism,  43°,  74°,  and  63°; 
sixth  prism,  23°,  90°,  and  67°. 

Set  of  six  prisms  in  neat  cardboard  box . 

74-280  EQUILATERAL  PRISM,  flint  glass,  square  ends,  30-millimeter  face,  4  inches  long . 

74-282  EQUILATERAL  PRISM,  flint  glass,  square  ends,  30-millimeter  face,  6  inches  long . 

74-285  EQUILATERAL  PRISM,  flint  glass,  square  ends,  50-millimeter  face,  optically  true  surface,  4  inches 
long  . Duty  Free 

74-287  EQUILATERAL  PRISM,  flint  glass,  square  ends,  40-millimeter  face,  about  2  inches  long,  surfaces 
optically  true . Duty  Free 

74-296  EQUILATERAL  PRISM,  crown  glass,  square  ends,  25-millimeter  face,  1%  inches  long . 

74-297  EQUILATERAL  PRISM,  crown  glass,  square  ends,  25-millimeter  face,  2  inches  long . 

74-305  RIGHT  ANGLE  PRISM  for  total  reflection,  angles  of  45  and  90°,  sides  25  by  25  millimeters,  length 

1  Yl  inches . 

74-307  RIGHT  ANGLE  PRISM  for  total  reflection,  angles  of  45  and  90°,  sides  38  by  38  millimeters,  length 

2  inches . 

74-315  FLINT  GLASS  PRISM,  refracting  angle  of  20°,  sides  41  millimeters,  length  \l/&  inches  .....' 


$9.50 

.60 

.76 

14.26 

10.60 

.36 

I 

.48 

.60 

.75 

.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


261 


SPECTROSCOPIC  PRISMS 


Used  by  express  permission  of  copyright  owner 

'  No.  74-367  No.  74-366 

Nos.  74-360  a-e,  to  Nos.  74-360  a-e 
Nos.  74-390  a-c  Nos.  74-400  a-c 

74-360  FLINT  GLASS  EQUILATERAL  SPECTRAL  PRISMS,  optically  true  surfaces,  square  ends. 

Refractive  Index  for  D  =  1.602;  Dispersion  C-F  —  1°  58';  Minimum  for  M/D  =  55°  20' 

a  b  c  d  e 

Side  .  25  30  35  40  50  millimeters 

Each,  Duty  Free  .  .  $4.76  6.26  6.26  7.40  9.76 

Each  from  Stock  .  6.26 

74-360  CROWN  GLASS  EQUILATERAL  SPECTRAL  PRISMS,  optically  true  surfaces,  square  ends. 

Refractive  Index  for  D  =  1.517;  Dispersion  C-F  =  41';  Minimum  for  M/D  =  50°  24' 

a  b  c  d  6 

Side  .  25  30  35  40  50  millimeters 

Each,  Duty  Free  .  .  $4.76  6.26  6.26  7.40  9.76 

Each  from  Stock  6.26 

74-366  CROWN  GLASS  SPECTRAL  PRISM,  angles  of  45  and  90  degrees,  cathetus  25  millimeters. 

Duty  Free  $6.26 

74-367  CROWN  GLASS  SPECTRAL  PRISM,  angles  of  45  and  90  degrees,  cathetus  50  millimeters. 

Duty  Free  9.40 

74r-370  RUTHERFORD’S  COMPOUND  ACHROMATIC  PRISMS,  consisting  of  a  flint  glass  prism  luted 
between  two  crown  glass  prisms. 

3.  t)  C  d  6 

Side  .  20  30  40  50  60  millimeters 

Each,  Duty  Free  .  .  $9.76  14.60  23.26  38.60  49.76 

74-380  AMICI’S  DIRECT  VISION  PRISMS,  consisting  of  three  prisms  so  arranged  as  to  give  direct  vision. 

abed 

Cross-cut  .  10  20  30  40  millimeters 

Each,  Duty  Free  .  .  $4.76  12.26  18.60  39.76 

74-390  EQUILATERAL  QUARTZ  PRISMS,  with  the  refracting  edge  perpendicular  to  the  optical  axis. 

a  b  c 

Side  .  25  35  45  millimeters 

Each,  Duty  Free  .  .  $8.60  14.26  22.00 

74-400  EQUILATERAL  QUARTZ  PRISMS,  having  the  refracting  edge  parallel  to  the  optical  axis 

a  b  c 

Side  .  25  35  45  millimeters 

Each,  Duty  Free  .  .  $8.60  14.26  22.00 


262 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


74-410 

74-420 

74-426 


74-430 

74-432 

74-434 

74-436 

74-438 


MISCELLANEOUS  PRISMS 


No.  74-410  No.  74-426 


ACHROMATIC  PRISMS,  faces  polished  optically  true  and  carefully  fitted. 

a  b  c 

Aperture  .  25  35  50  millimeters 

Each,  Duty  Free  .  .  .  $6.76  7.40  9.80 

WEINHOLD’S  DEMONSTRATION  PRISMS  for  explaining  dispersion  and  achromatism  without 

deviation  of  the  mean  ray. 

Consists  of  three  prisms,  two  of  crown  and  one  of  flint  glass,  ground  and  polished  optically  true. 

Set  of  three,  without  mounting  of  any  kind . Duty  Free  $9.76 

POLYPRISM  for  showing  that  the  angle  of  deviation  increases  with  the  refractive  index. 

Each  prism  consists  of  four  glass  parts  which  are  unequally  refringent,  luted  to  form  a  prism.  Length 
of  side,  35  millimeters . , . .  Duty  Free  9.26 


No.  74-430 


No.  74-432  Nos.  74-434  to  74-436 


IMPROVED  CAST  HOLLOW  PRISM.  The  design  illustrated  above  pictures  our  new  model 
hollow  prism,  indestructibly  constructed  of  cast  metal  with  openings  in  two  sides  closed  in  an 
ingenious  manner  by  optical  plate  glass.  This  prism  will  be  found  adequate  for  most  laboratory 
work,  and  results  are  entirely  satisfactory. 

It  is  finished  with  a  durable  dull  black  coating . 


OPTICAL  GLASS  CEMENTED  FACE  HOLLOW  GLASS  PRISM,  two  faces  cemented  and  polished, 
the  third  face  blackened,  ground  glass  stopper,  height  65  millimeters,  face  32  millimeters  .  .  . 


HOLLOW  GLASS  PRISM,  equiangular,  of  best  ground  and  polished  crystal  plate  glass,  with  ground 
glass  stopper,  partition  cemented  in  the  middle  for  two  liquids.  Mounted  on  wooden  foot,  120 
millimeters  high  by  80  millimeters  face . Duty  Free 


■,  same  as  above,  but  100  millimeters  by  60  millimeters  wide 


Duty  Free 


$3.76 

6.60 

7.60 

6.26 


No.  74-438 

WEDGE-SHAPED  TROUGHS,  a  pair  of  wedge-shaped  troughs  each  6  inches  long  by  2  inches  wide, 

refractive  angles  of  20° . Duty  Free  $6  60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


263 


MISCELLANEOUS  PRISMS 


No.  74-460 


No.  74—460 


74-460  MOUNTED  EQUILATERAL  PRISM.  This  is  a  4-inch  equilateral  prism,  mounted ’on  the  Hall 
Universal  Stand  as  illustrated.  This  stand  can  be  raised  and  lowered  to  any  desired  height  or  in¬ 


clined  to  any  angle.  It  is  handsomely  finished  and  the  base  offers  a  substantial  support  ....  $6.76 

74-462  - ,  similar  to  above,  but  prism  6  inches  long .  6.76 

74-466  MOUNTED  TOTAL  REFLECTION  PRISM,  consisting  of  a  right  angle  prism,  flint  glass,  angles  of 

45°  and  90°  mounted  on  stand  as  illustrated  in  No.  74-460  .  6.76 


74-460  WEINHOLD’S  DEMONSTRATION  PRISM  for  explaining  dispersion  and  achromatism  without 
deviation  of  the  mean  ray. 

This  apparatus  consists  of  a  set  of  three  prisms  conveniently  mounted  for  the  greatest  utility 
and  ease  of  adjustment.  The  lower  combination  gives  an  achromatic  arrangement,  while  the  upper 
gives  direct  vision  dispersion.  For  demonstration,  best  results  are  secured  by  arranging  the 
prisms  so  that  the  field  is  divided  into  three  portions,  the  center  of  which  is  due  to  the  combina¬ 
tion.  (See  illustration  at  right.) 

Complete  with  three  prisms,  each  separately  mounted,  with  supporting  stand  ....  Duty  Free 


No.  74-480 


74-470  DIRECT  VISION  PRISM,  after  the  original  specifications  of  the 
late  Mr.  Eaton  of  Brooklyn,  N.  Y.,  for  projection  of  spectra 
on  a  screen. 

This  prism  consists  of  a  combination  of  two  prisms,  one  of  dense 
glass,  the  other  a  hollow  prism  which  in  use  is  filled  with  carbon 
bisulphide,  the  angles  of  each  of  which  are  very  nicely  cal¬ 
culated,  giving  a  direct  vision  spectrum  of  large  dispersion. 
At  a  distance  of  twenty  feet  from  the  screen,  with  a  J^-size 
objective,  it  is  possible  to  secure  a  clear  spectrum  band  6  feet 
long  by  2  feet  wide. 

Mounted  on  rod  telescoping  into  neat  tripod  stand . 

74-480  POLYPRISM,  illustrating  the  phenomena  of  multiple  refrac¬ 
tion. 

This  apparatus  consists  of  a  cylindrically  shaped  wooden  frame, 
in  one  end  of  which  is  mounted  a  prism,  the  face  of  which  is 
cut  into  a  series  of  very  small  prisms.  The  other  end  is  pro¬ 
vided  with  an  aperture,  so  that  an  object  such  as  a  line  may  be 
viewed. 

Curious  and  interesting  modifications  of  the  shape  of  an  object 
are  noted.  The  apparatus  is  small,  easily  handled,  and  will 
be  found  of  considerable  qualitative  value . 


264 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


OPTICAL  INSTRUMENTS 

TELESCOPES  —  SEXTANTS 


No.  76-30 

76-30  ACHROMATIC  TELESCOPE,  extra  quality,  morocco-covered  body,  polished  brass  slides,  cap  for 
object  glass  and  sliding  cover  for  eye  lens.  Length,  closed,  534  inches,  three  draws  to  14  inches  long, 
magnifying,  power  12  diameters . $3.26 

ASTRONOMICAL  TELESCOPES 


V,.  No.  76-80 

Among  the  high-grade  telescopes  now  presented  to  the  public  no  instruments  have  become  so  widely  or  so  de¬ 
servedly  popular  as  the  line  herewith  listed.  Due  to  improved  methods  of  manufacture  and  the  consequent  dimin¬ 
ishing  of  the  manufacturing  cost,  a  high-grade  instrument,  like  an  astronomical  telescope,  has  ceased  to  be  the  mere 
instrument  of  a  profession,  and  the  prices  have  become  so  reasonable  that  it  is  possible  for  a  school  or  college  to  num¬ 
ber  one  among  its  equipment. 

The  instruments  herewith  listed  are  noted  for  their  optical  range  and  capacity.  The  mechanical  features  are 
unexcelled  and  all  accessories  are  of  the  same  high  quality.  The  policy  of  the  manufacturers  has  been  to  make  of 
each  telescope  an  instrument  reliable  in  quality  and  moderate  in  price.  Each  instrument  is  furnished  fully  equipped 
for  good  work  by  day  or  night. 


76-60 

76-66 

76-60 


76-66 

76-70 

76-76 

76-60 


76-86 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


PORTABLE  ASTRONOMICAL  TELESCOPE.  This  instrument  has  been  designed  light  in  weight 
for  use  on  a  table  or  stand.  It  has  the  same  high  optical  qualities  as  have  all  the  models  of  this 
manufacturer.  Body  of  telescope,  sliding  tube  for  eye-pieces,  and  tubular  support  for  table  tripod, 
are  of  polished  brass.  Feet  of  tripod  are  wrought  steel,  japanned.  The  instrument  has  detachable 
sun-glass,  brass  cap  for  protection  of  object  glass,  and  rack  and  pinion  focusing  adjustment.  Three 
eye-pieces  are  furnished:  one  terrestrial  eye-piece,  power  45,  and  two  astronomical  eye-pieces, 
powers  50  and  114.  Diameter  of  object  lens,  3  inches;  length  of  tube  when  closed,  about  39  inches, 
—  when  extended,  about  59  inches. 

Telescope  enclosed  with  table  tripod  in  neat  wooden  box . Duty  Free 

- ,  same  as  above,  but  provided  with  large  hardwood  tripod  in  addition  to  the  table  tripod  above  fur¬ 
nished.  Enclosed  in  neat  wooden  box . Duty  Free 

ASTRONOMICAL  TELESCOPE.  This  instrument  is  somewhat  more  elaborate  than  the  preceding 
and  has  a  greater  focal  length.  In  addition,  the  tripod  is  especially  designed  for  stability  and 
strength  and  is  furnished  with  a  simple  but  effective  cranking  adjustment  for  increasing  or  decreas¬ 
ing  the  height  of  the  telescope.  It  is  made  of  finely  finished  mahogany.  Its  construction  insures 

•  rigidity  and  affords  special  steadiness  of  the  telscope. 

Each  instrument  includes  a  sun-glass,  and  three  eye-pieces,  one  terrestrial  and  two  astronomical. 
The  power  of  the  terrestrial  eye-piece  is  54  and  the  powers  of  the  astronomical  eye-pieces  are  60 
and  120.  The  size  of  the  object  lens  is  3  inches;  the  telescope  body  with  cap  is  of  polished  brass; 
length  of  tube  when  closed,  about  46  inches,  —  extended,  about  63  inches. 

The  instrument  is  furnished  in  wooden  box  with  handle,  lock,  and  key . Duty  Free 

- ,  similar  to  above,  except  that  the  object  lens  is  334  inches  in  diameter  and  the  telescope  is  some¬ 
what  larger  in  size.  The  magnifying  power  of  the  terrestrial  eye-piece  is  59.  The  powers  of  the 


astronomical  eye-pieces  are  65  and  130.  Length  of  tube  closed  is  about  48  inches,  —  extended, 
68  inches. 

In  neat  wooden  box  with  handle,  lock  and  key . Duty  Free 


- ,  same  as  above,  but  provided  with  a  “finder.”  This  telescope  is  provided  with  a  sun-glass  and 

five  eye-pieces:  two  terrestrial,  magnifying  49  and  59  respectively,  and  three  astronomical  eye¬ 
pieces,  magnifying  respectively  65,  88  and  146  times. 

Enclosed  in  wooden  box . Duty  Free 

- ,  same  as  above,  except  that  object  lens  is  3%  inches  in  diameter,  and  the  instrument  is  fur¬ 
nished  with  two  terrestrial  eye-pieces,  powers  55  and  66,  and  four  astronomical  eye-pieces,  powers 
74,  99,  147,  and  221.  Length  of  tube  closed,  about  53  inches,  —  extended,  about  73  inches. 

Enclosed  in  wooden  box . Duty  Free 

ASTRONOMICAL  TELESCOPE  (illustrated  on  preceding  page).  Uniting  all  the  chief  advantages 
of  the  types  previously  listed,  this  telescope  is  also  provided  with  still  another  desirable  feature. 
Each  instrument  is  provided  with  two  slow  motions,  making  it  possible  for  the  astronomical  observer 
to  control  the  telescope  with  greater  precision  and  with  the  least  possible  vibration.  Tangent 
screws  encased  by  rods  that  may  be  slowly  turned  by  a  very  slight  motion  of  the  hand  enable  the 
observer  to  keep  the  object  in  field  of  view. 

The  telescope  includes  “finder,”  sun-glasses  for  the  astronomical  eye-pieces  and  five  eye-pieces;  two 
terrestrial  eye-pieces,  powers  49  and  59,  and  three  astronomical,  powers  65,  88  and  146.  The 
size  of  the  object  lens  is  3)4  inches.  Telescope  body,  etc.,  are  of  polished  brass,  with  brass  cap  to 
protect  the  eye  lens.  The  tripod  is  especially  strong  and  stable,  and  is  constructed  of  mahogany, 
and,  in  addition  to  the  slow  motion  adjustments  already  noted,  has  a  special  cranking  mechanism 


for  adjustment  of  the  height.  Length  of  tube  when  closed,  about  48  inches,  —  extended,  about 
68  inches. 

In  wooden  box  with  handle,  lock  and  key . Duty  Free 


— ,  same  as  above,  but  larger  in  size.  Object  lens  3%  inches  in  diameter.  Six  eye-pieces:  two 
terrestrial  eye-pieces,  powers  55  and  66,  and  four  astronomical,  powers  74,  99,  147  and  221.  Length 
of  tube  when  closed,  about  53  inches,  —  extended,  about  73  inches . Duty  Free 


265 


266  L .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


These  models  consist  of  lenses  mounted  in  holders  placed  appropriately  for  the  best  definition. 

The  holders  are  mounted  on  a  cross-head  attached  to  a  neatly  finished  wood  stand.  The  paths  whicl> 
the  rays  take  are  sketched  on  the  flat  face  of  the  cross-head.  These  models  will  be  found  instructive  and 
as  the  magnification  and  definition  are  excellent  they  will  be  found  of  great  utility. 


No.  75-164 


No.  .76-150 


76-150  GALILEO’S  TELESCOPE  MODEL,  comprising  two  lenses,  the  object  glass,  and  a  diverging  or 
double  concave  eye-piece.  This  instrument  illustrates  the  common  Opera  Glass,  giving  an  erect 
image .  . $4.60 

75-151  ASTRONOMICAL  TELESCOPE  MODEL,  consisting  of  two  lenses,  one  the  condensing  eye-piece 
and  the  other  the  object  glass.  In  comparison  with  No.  75-154,  Model  of  the  Microscope,  it  will 
be  seen  that  this  astronomical  telescope  is  analogous  to  the  microscope,  differing  in  the  respect 
that,  in  the  microscope  the  object  being  seen  through  the  object  glass  the  image  formed  must  be 
on  the  principal  focus  and  is,  therefore,  greatly  magnified,  so  that  both  the  object  glass  and  the 
eye-piece  magnify,  while  in  the  astronomical  telescope  the  heavenly  body  being  at  a  great  distance 
the  rays  are  parallel  and  the  image  formed  on  the  principal  focus  of  the  object  glass  is  much  smaller 
than  the  object.  There  is,  therefore,  little  magnification  except  that  secured  by  the  eye-piece, 
which  usually  is  of  short  focal  length. 

The  lines  which  represent  the  path  of  the  rays  bring  this  out  very  clearly  in  object  models  .  .  .  6.40 

75-162  TERRESTRIAL  TELESCOPE  MODEL,  consisting  of  two  condensing  lenses  placed  between  the 
object  glass  and  the  eye-piece.  It  will  be  noted  that  this  telescope  differs  from  the  astronomical 
telescope  in  that  it  produces  images  in  their  right  positions .  7.15 

75-163  TELESCOPE  MODELS,  as  listed  above,  showing  the  construction  of  the  principal  telescopes,  set 

of  three  i . 18.00 

75- 164  MICROSCOPE  MODEL,  consisting  of  two  lenses,  one  the  objective,  the  other  the  eye-piece  ....  4.50 

76- 166  DEMONSTRATION  MICROSCOPE,  after  Millikan  and  Gale’s  “A  Laboratory  Course  in  Phys¬ 

ics”  (Experiment  45),  for  determining  the  magnifying  power  of  a  microscope. 

The  apparatus  consists  of  a  brass  tube,  on  either  end  of  which  are  placed  strips  with  apertures. 

Over  one  end  is  fastened  a  linen  tester,  No.  74-235.  Apparatus  complete  with  two  linen  testers  .  1.05 

75- 166  TUBE  only,  without  linen  testers .  .20 

« 

76- 161  RULED  CARDBOARD  STRIP,  after  Fuller  and  Brownlee  (Experiment  49A) . 30 

75-163  CARDBOARD  INDEX  STRIP,  after  Fuller  and  Brownlee  (Experiment  49A) . .  .20 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


267 


76-165  SEXTANT,  for  measuring  the  angle  between  any  two  distant  objects.  This  is  a  universal,  durably 
constructed  aluminum  model,  divided  on  main  scale  to  read  to  degrees.  The  vernier  on  index  arm 
is  graduated  so  that  six  divisions  on  vernier  equal  five  on  the  main  scale. 

This  model  must  not  be  confused  with  a  number  of  cheap  models  at  present  on  the  market,  as  this 
is  an  accurately  working  instrument  provided  with  most  of  the  adjustments  of  an  engineer’s 
and  mariner’s  expensive  metal  sextant  . $14.00 

76-170  REFLECTING  SEXTANT  for  measuring  the  angle  between  any  two  distant  points. 

This  is  an  accurately  constructed,  brass  sextant  capable  of  exact  determinations,  reading  by  ver¬ 
nier  to  5  minutes  of  arc.  It  is  provided  with  an  astronomical  telescope  of  12  millimeters’  aper¬ 
ture  and  with  blend  glasses  as  illustrated . Duty  Free  .  .  . 


DIFFRACTION  OF  LIGHT 


« 


No,  77-76 


77-76  SUN  SPECTRUM  CHART,  hand  painted  on  linen,  spectrum  band  about  48  inches  long  by  7  inches 
wide.  Frauenhofer  lines  indicated  and  colors  carefully  matched  and  work  well  executed.  Mounted 
in  frame  to  occupy  wall  space  of  about  5X2  feet . Duty  Free  .  .  . 

77-80  SPECTRUM  CHART,  after  Kirchhoff  and  Bunsen,  showing  beautifully  the  spectrum  of  the  Sun, 

K,  Rb,  Cs,  Tl,  Na,  Li,  Ca,  Sr  and  Ba.  Mounted  on  linen  back  with  common  rollers  .  .  .  ....  $4.26 

77-82  SPECTRUM  CHART,  after  Kirchhoff  and  Bunsen,  showing  the  following  spectra:  In,  C,  Bo,  Mn,  Pb, 

Cu,  Co,  Ni  and  Fe.  Mounted  on  linen  back  with  common  rollers .  4.26 

77-86  SPECTRUM  CHART,  illustrating  the  Solar  Spectrum. 

This  Chart  consists  of  a  strip  of  paper  on  which  the  spectrum  is  beautifully  lithographed.  It  is  about 

80  centimeters  long  and  mounted  on  heavy  cardboard.  The  various  Frauenhofer  lines  are  indicated  1.60 

21-210  COLOR  DISCS  for  quantitative  work  in  color  mixing  and  color  analysis. 

Set  of  seven  10-inch  discs  of  primary  colors,  one  each  of  black  and  white,  and  a  percentage  circular 

protractor  for  quantitative  work.  (For  illustration,  see  Section  21) .  2.00 

21-225  COMBINATION  NEWTON’S  COLOR  DISC  for  showing  white  light  when  fixed  portions  of  pri¬ 
mary  colors  are  rapidly  rotated.  (For  description  and  illustration,  see  Section  21) .  1.60 

77-90  COLORED  GLASS  PLATES  for  analysis  and  study  of  light. 

These  plates  are  selected  colored  plates  of  the  best  “pot  glass”  colors.  They  are  furnished  10  centi¬ 
meters  square  in  the  following  colors:  red,  orange,  yellow,  green,  blue,  indigo  and  violet. 

Per  set  of  seven  colors .  1.60 


268 


L .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


THE  VON  NARDROFF  COLOR  APPARATUS 

DESIGNED  FOR  THE  STUDY  OF  COLOR  PHENOMENA 


An  Attachment  for  the  Projection  Lantern  or  Porte  Lumiere 
Made  under  the  personal  supervision  of  Mr.  F.  W.  Huntington 


77-100  VON  NARDROFF  COLOR  APPARATUS.  This  apparatus  was  designed  by  Dr.  Von  Nardroff, 
Principal  of  the  Stuyvesant  High  School,  New  York  City,  for  the  convenient  and  satisfactory  study 
of  color  phenomena  where  only  one  Projection  Lantern  is  available.  Our  method  of  mounting  is 
such  that  it  is  equally  well  adapted  for  use  with  the  Porte  Lumiere. 

Briefly,  it  is  an  attachment  that  converts  an  ordinary  Projection  Lantern  into  a  triple  lantern  in  which 
each  of  the  three  beams  of  light  is  independent  both  as  to  intensity  and  direction.  The  general  form 
and  design  will  be  clearly  indicated  by  the  cuts  above,  showing  two  positions. 


maxwell’s  primary  hues. 

Fit.  ■ 


Fig.  * 


COMPLEMENTARY  HUES. 
F'S  J- 


EXPERIMENTS 


Fig.  4. 


A  STUDY  OF  PRIMARIES  AND  SECONDARIES  (see  Fig.  1).  The  red,  green,  and  blue  glasses  provided 
with  the  apparatus  are  placed  in  the  glass  holders  shown  in  the  diagram.  By  a  movement  of  the 
lens  arm  these  circles  of  red,  green,  and  blue  may  be  overlapped  either  in  whole  or  in  part  as  desired 
and,  by  means  of  the  diaphragms,  the  intensity  of  strength  of  each  color  readily  regulated.  The 
effect  of  mixing  the  primaries  in  any  desired  portion,  in  pairs  or  in  triples,  is  readily  seen. 

FALSE  PRIMARIES  (see  Fig.  2).  In  this  illustration  the  glasses  selected  should  be  the  purple,  yellow,  and 
blue-green,  and  by  proper  manipulation  of  the  diaphragms  all  possible  hues,  as  well  as  white,  may 
be  obtained. 

COMPLEMENTARY  HUES  (see  Fig.  3)  are  easily  illustrated  by  carefully  choosing  the  pairs  of  colored  glasses 
to  obtain  the  desired  results. 

“THE  GREEN  QUESTION”  is  solved  by  super-imposing  the  yellow  and  blue  glasses  in  the  single  slide 
holder  of  the  apparatus  and  again  inserting  the  same  glasses  in  separate  slide  holders,  adding  the 
beams  by  over-lapping  on  the  screen,  noting  that  a  pure  white  light  is  obtained. 

CONTRASTING  EFFECTS  (see  Fig.  4)  are  strikingly  illustrated  when  a  saturated  color,  such  as  green,  is  pro¬ 
jected  and  the  white  disc  arranged  to  partially  over-lap  turned  on;  the  over-lap,  which  is  really 
a  tint,  appearing  nearly  white,  while  the  remaining  white  appears  strongly  colored  of  the  com¬ 
plementary  hue.  If  the  order  of  projection  is  reversed,  the  sudden  appearance  of  the  white  is 
very  impressive. 

A  STUDY  OF  TINTS  is  easily  made  by  adding  to  the  white  beam  a  colored  beam  adjusted  for  intensity. 

OTHER  EXPERIMENTS.  Many  additional  experiments  will  suggest  themselves  to  the  user  after  he  has  be¬ 
come  familiar  with  the  apparatus  and  commences  to  learn  some  of  its  possibilities;  such,  for  in¬ 
stance,  as  three  equally  bright  beams  being  made  to  partially  over-lap.  The  remaining  portions 
of  the  beams  will  present  intensities  as  the  ratio  of  1:  2:  3.  Again,  projecting  on  the  screen  a  com¬ 
pound  white,  holding  an  opaque  body  in  the  path  of  the  ray,  a  very  remarkable  shadow  effect  will 
be  produced. 

Price  mounted  as  illustrated .  .  .  $32.00 


; 


! 


! 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


269 


SPECTRAL  APPARATUS 


Nos.  77-126  to  77-126 


77-126  DIRECT  VISION  POCKET  SPECTROSCOPE  for  use  in  experiments  in  Spectrum  Analysis. 

This  instrument  consists  of  a  combination  of  three  prisms  giving  a  considerable  dispersion.  It  will 
show  many  of  the  Frauenhofer  lines,  the  bright  lines  of  the  metals  and  gases  and  the  absorption 
bands  in  colored  gases,  crystals,  or  liquids.  It  is  provided  with  an  adjustable  slit  operated  by  a 
small  micrometer  screw.  This  spectroscope  has  an  achromatic  lens  and  is  of  excellent  quality 
throughout. 

Enclosed  in  velvet-lined  case . $9.00 

77-126  —  — ,  same  as  above,  but  fitted  with  a  comparison  prism  which  will  show  two  spectra  in  the  field  of 
view  at  the  same  time,  so  that  they  may  be  conveniently  compared. 

Enclosed  in  velvet-lined  case . Duty  Free  14.60 


77-160  DEMONSTRATION  SPECTRAL  APPARATUS  AND  GONIOMETER,  —  a  goniometer  or  spec¬ 
trometer  of  simple  design  but  accurate  construction,  in  which  all  lenses,  diaphragms  and  slit  are 
separately  mounted  and  arranged  for  adjustment  along  nickel-plated  graduated  metal  bars.  The 
prism  table  and  circle  is  accurately  divided  on  metal  to  two  degrees. 

Although  primarily  designed  for  demonstration  purposes,  it  will  be  found  of  unusual  value  as  a 
student’s  instrument,  in  that  the  student  is  enabled,  not  only  to  use  the  instrument  as  a  spectral 
apparatus  with  a  fair  degree  of  accuracy,  but  also  to  use  it  with  a  correct  understanding  of  con¬ 
struction  of  telescope  and  collimator  and,  from  observation  of  correct  position  of  parts  arranged 
openly  on  this  simple  design,  to  clearly  understand  the  more  complex  instruments. 

Constructed  of  metal  throughout,  handsomely  nickel-plated  and  oxidized.  Complete  with  Holders, 

Slit  and  Lenses,  but  without  Prism . $19.80 


77-162  STUDENT’S  SPECTROSCOPE.  Many  teachers  have 
felt  the  need  of  an  inexpensive  instrument  capable  of 
demonstrating  to  students,  in  a  convenient  manner  and 
without  loss  of  time,  the  methods  of  spectrum  analysis. 

The  spectroscope  illustrated  is  provided  with  a  set  of 
prisms  of  high  dispersion  and  yields  a  wide  spectrum, 
showing  a  large  number  of  Frauenhofer  lines.  The  ad¬ 
justment  of  focal  length  is  secured  by  means  of  a  small 
handle  sliding  along  the  tube.  The  fixed  slit  at  one 
end  is  covered  by  a  glass  plate  so  as  to  be  completely 
protected  from  dust.  ,  The  spectrum  in  consequence 
will  be  free  from  cross-lines.  The  instrument  is  mount¬ 
ed  on  a  neat  wooden  stand  and  is  provided  with  holder 
for  test  tubes . Duty  Free 


No.  77-162 


270 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


77-170  ADVANCED  SPECTROSCOPE.  This 
instrument  is  especially  designed  for 
high  school  and  elementary  college 
work.  It  is  furnished  completely 
equipped  with  all  essential  parts. 

All  mechanical  details  are  well  con¬ 
structed  and  nicely  fitted;  all  optical 
parts  are  of  the  best.  The  telescope 
is  adjustable,  has  an  aperture  of  about 
20  millimeters  and  a  focal  length  of 
about  160  millimeters.  The  collimator 
is  provided  with  a  comparison  prism 
and  is  of  the  same  dimensions  as  the 
telescope.  A  separate  tube  contains 
the  scale.  The  instrument  is  mounted 
adjustably  in  a  neatly  finished  tripod 
stand.  It  is  furnished  with  a  60-degree 
flint  glass  prism  and  provided  with 
a  cover  for  same  .  .  .  Duty  Free 


No.  77-170 


No.  77-175 


77-176  UNIVERSALLY  ADJUSTABLE  SPECTROMETER,  after  V.  v.  Lang. 

The  adaptability  of  this  instrument  to  most  spectrometric  work  has  made  it  one  of  the  most  popular 
spectrometers  in  use.  Constructed  by  one  of  the  most  prominent  European  manufacturers,  it 
has  received  every  attention  in  structure.  Mechanical  parts  are  accurately  constructed  and  care¬ 
fully  fitted;  optical  parts  calculated  to  a  nicety  for  the  work  for  which  the  instrument  is  intended. 

The  circle  is  120  millimeters  in  diameter  with  graduations  on  silver  to  3^  degree.  To  facilitate  in  the 
reading,  the  instrument  is  provided  with  two  verniers  with  magnifiers  which  facilitate  readings 
to  60  seconds  of  arc.  The  telescope  has  an  aperture  of  20  millimeters,  is  provided  with  rack  and 
pinion  adjustment  and  may  be  rotated  about  the  vertical  axis.  The  collimator  has  same  diameter 
as  the  telescope  and  is  provided  with  a  slit  with  micrometer  screw  adjustment,  the  extent  of  open¬ 
ing  being  indicated  on  the  graduated  drum.  The  prism  table  is  adjustable  in  height  and  may 
be  leveled  by  three  small  thumb  screws  noted  in  the  illustration.  The  instrument  is  mounted  on 
a  neatly  finished  tripod  base  provided  with  leveling  screws.  All  necessary  adjustments  for  tele¬ 
scope  tube  and  collimator  and  locking  device  for  the  latter  are  provided.  This  instrument  will 
give  universal  satisfaction . Duty  Free 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


271 


74-360 


74-360 


74-366 

74-367 

74-370 


77-226 

77-226 

77-227 

77-228 

77-236 

77-236 

77-246 


Used  by  express  permission  of  copyright  owner 


No.  74-367 

Nos.  74-360  a-e  to 
Nos.  74-390  a-c 


No.  74-366 
Nos.  74-360  a-e 

Nos.  74-400  a-c 


FLINT  GLASS  EQUILATERAL  SPECTRAL  PRISMS,  optically  true  surfaces,  square  ends. 
Refractive  Index  for  D  =  1.602.  Dispersion  C-F  —  1°  58'.  Minimum  for  M/D  =  55°  20' 


3.  1)  c  d  0 

Side  .  25  30  35  40  50  millimeters 

Each,  Duty  Free  .  .  $4.76  6.26  6.26  7.40  9.76 

Each  from  Stock  .  6.26 

CROWN  GLASS  EQUILATERAL  SPECTRAL  PRISMS,  optically  true  surfaces,  square  ends. 
Refractive  index  for  D  =  1.517;  Dispersion  C-F  =  41°.  Minimum  for  M/D  =  50°  24' 

a  b  c  d  e 

Side  .  25  30  35  40  50  millimeters 

Each,  Duty  Free  .  .  $4.76  6.26  6.26  7.40  9.76 

Each  from  Stock  6.26 


CROWN  GLASS  SPECTRAL  PRISM,  angles  of  45  and  90  degrees,  cathetus  25  millimeters. 

Duty  Free 

CROWN  GLASS  SPECTRAL  PRISM,  angles  of  45  and  90  degrees,  cathetus  50  millimeters. 

Duty  Free 

RUTHERFORD’S  COMPOUND  PRISMS,  consisting  of  a  flint  glass  prism  luted  between  two  crown 


glass  prisms. 

a 

b 

c 

d 

e 

Side  . 

20 

30 

40 

50 

60  millimeters 

Each,  Duty  Free  . 

.  $9.76 

14.60 

23.25 

38.50 

49.76 

Nos.  77-226  to  77-236 


No.  77-246 


GEISSLER  SPECTRUM  TUBE,  filled  with  carbon  dioxide . 

- ,  filled  with  hydrogen  gas . 

- ,  filled  with  nitrogen  gas . 

- ,  filled  with  oxygen  gas . 

GEISSLER  SPECTRUM  TUBE,  most  carefully  constructed,  evacuated,  and  filled  with  pure  argon  gas 

- ,  same  as  above,  but  filled  with  pure  helium . 

GEISSLER  SPECTRUM  TUBE  for  exhausting  and  filling  with  whatever  gas  desired.  Fitted  with 
two  carefully  ground  glass  cocks  . 


$6.25 

9.40 


$1.96 

1.96 

1.96 

1.96 

7.76 

7.76 


1.96 


272  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ABSORPTION  TROUGHS 


No.  77-266 


No.  77-267 


No.  77-270 


77-266  ABSORPTION  TROUGH,  U-SHAPED,  for  use  as  an  absorption  vessel,  light  filter  or  for  projec¬ 
tion  of  living  matter  in  liquids. 

This  trough  is  durably  constructed  and  the  cementing  is  guaranteed  not  to  leak,  being  baked  in 
special  furnaces  at  1000°  F.  Size  50  millimeters  high,  20  millimeters  wide,  and  4  millimeters 
deep . . . 

77-267  ABSORPTION  TROUGH,  square  shaped,  with  round  bore,  the  same  careful  construction  as  above. 

Inside  measurement  20  X  4  millimeters . 


77-270  DOUBLE  ABSORPTION  TROUGH  for  comparing  two  liquids  simultaneously,  same  careful  con¬ 
struction  as  above.  Inside  measurement  of  each  partition,  40  X  25  X  10  millimeters . 


No.  74-438 


74-438  WEDGE-SHAPED  TROUGHS,  a  pair  of  prism-shaped  troughs,  each  6  inches  long  by  2  inches  high. 

Refractive  angles  of  20  degrees . Duty  Free 


No.  77-300 


77-300  ADJUSTABLY  MOUNTED  FRESNEL’S  INTERFERENCE  MIRRORS  for  illustrating  interference 

of  light  by  reflection. 

The  apparatus  consists  of  two  optically  plane  black  glass  mirrors  the  polished  surfaces  of  which  extend 
right  up  to  the  line  of  intersection  of  the  two  faces.  These  mirrors  are  provided  with  Micrometer 
Screw  Adjustments,  so  that  the  angle  between  them  may  be  varied  within  short  limits.  For 
normal  use,  these  mirrors  should  be  at  nearly  180  degrees  of  angle  in  order  to  get  proper  inter¬ 
ference.  By  means  of  the  micrometer  screw  attachment,  however,  the  complete  system  of  fringes 
can  be  caused  to  pass  in  succession  over  any  desired  part  of  the  screen.  The  mirror  frame  is  at¬ 
tached  to  a  rod  for  use  with  our  No.  6-810  Right  Angle  Clamp  for  use  on  an  Optical  Bench 

Duty  Free 

77-305  MOUNTED  FRESNEL’S  BI-PRISM  for  showing  interference  of  light  by  transmission.  Duty  Free 


$1.66 

1.45 

4.86 


$6.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


273 


DIFFRACTION  GRATINGS 

77-316  PRISM  GRATINGS  for  spectroscopic  and  lantern  work.  Prism  Gratings  have  been  designed  for 
obtaining  direct  vision  spectra  of  great  dispersion,  while  their  brilliancy  is  far  greater  than  plate 
gratings.  They  are  made  of  varying  angles  and  sizes  to  suit  requirements  and  are  equal  in  many 
cases  to  4  to  6  flint  prisms,  the  amount  of  dispersion  being  affected  by  the  angle  at  which  the 
prism  is  tilted.  The  surfaces  of  a,  b,  and  c  are  accurate  to  1/500,000  and  of  d  and  e  to  1/50,000 
of  an  inch. 

a  b  c  d  e 

Size  of  Face  .  .  .61  X  48  38  X  30  28  X  19  64  X  38  28  X  19  millimeters 

Each,  Duty  Free  .  ...  ...  ...  ... 


Nos.  77-320  to  77-326 

77-320  TRANSMISSION  DIFFRACTION  GRATING.  These  gratings  are  moulded  replicas  of  Row¬ 
land’s  celebrated  metallic  gratings  of  14,438  lines  to  the  inch.  They  are  mounted  on  parallel 
plate  glass  and  are  suitable  for  work  of  the  highest  class,  both  visual  and  photographic,  as  well  as 
for  projection  purposes,  and  give  a  brilliant  and  pure  normal  spectra.  Wave  length  measurements 
may  be  safely  taken,  as  each  grating  has  the  number  of  lines  per  inch  marked  on  it.  Size,  28  X  19 
millimeters . Dutv  Free  .  .  . 

77-322  -  — ,  same  quality  as  above,  but  54  X  35  millimeters . Duty  Free  .  .  . 

77-326  TRANSMISSION  DIFFRACTION  GRATING,  same  size  as  No.  77-322,  but  on  optically  worked 

glass,  giving  a  very  brilliant  spectrum . Duty  Free  .  .  . 


No.  77-360 

77-360  NEWTON’S  RINGS  for  illustrating  colors  of  thin  plates,  demonstrating  interference  of  light,  etc. 

This  apparatus  consists  of  two  brass  rings  between  which  are  locked  two  glasses,  one  plane  and  the 
other  convex,  of  very  long  focus.  The  method  of  locking  the  two  rings  is  such  that  by  means  of 
the  screws,  the  pressure  may  be  regulated.  Diameter  of  glasses,  1 inches. 

If  the  two  surfaces  are  exposed  to  ordinary  light  in  front  of  the  window,  so  as  to  reflect  light,  there 
is  seen  at  the  point  of  contact  a  black  spot  surrounded  by  6  or  7  colored  rings,  the  tints  of  which 
become  gradually  less  strong.  If  the  glasses  are  viewed  by  transmitted  light,  the  center  of  the 
ring  is  white  and  each  of  the  colors  is  exactly  complementary  of  that  of  the  rings  by  reflection. 
If  exposed  to  light  from  a  monochromatic  flame,  an  interesting  study  of  the  colored  rings  presents 


itself . $  1.45 

77-362  NEWTON’S  RINGS,  similar  to  above  but  of  larger  size.  Diameter,  16  centimeters.  Duty  Free  13.50 
77-376  INTERFERENCE  OF  LIGHT  PLATES,  after  Millikan  and  Gale,  Figure  391 . Pair  .  .46 


274 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


POLARIZATION  STUDY  APPARATUS 


No.  78-40 


78-40  STUDENTS’  POLARIZATION  STUDY  OUTFIT  for  study  of  effects  of  polarized  light. 

There  is  perhaps  no  branch  of  Optics  so  neglected  and  yet  in  which  results  are  so  important  as  that 
of  Polarized  Light.  The  neglect  is  due  in  a  large  measure  to  the  elaborate  and  costly  apparatus 
designed  for  this  branch.  To  encourage  the  study  we  have  secured  from  our  European  correspond¬ 
ents  the  design  above  illustrated. 

With  this  comprehensive  outfit,  contained  in  a  polished  wooden  box,  each  part  appropriately  mounted 
and  a  compartment  for  each,  very  beautiful  results  may  be  obtained.  The  Polarizing  Black  Mirror 
is  mounted  at  one  end,  the  holder  for  the  Analyzer  at  the  other,  a  Holder  for  the  different  crystals 
between.  The  Analyzer  consists  of  a  Nicol’s  Prism  mounted  in  a  brass  tube.  Four  other  brass 
tubes  each  with  different  crystals  are  furnished  for  use  in  the  mounting  with  the  Analyzer.  Various 
Gypsum  Figures  and  Specimens  are  furnished  for  study  under  polarized  light. 

We  cannot  too  strongly  urge  the  use  of  this  simplified  Study  Outfit.  All  parts  are  carefully  made 
and  selections  of  crystals  and  specimens  are  those  best  adapted  to  study. 

Complete  as  illustrated . .  .  . Duty  Free  .  .  . 


No.  78-45 


No.  78-75 


78-46  PICKERING  POLARISCOPE  for  study  of  simple  objects  under  polarized  light. 

This  is  a  simple  form  of  polariscope  in  which  the  Polarizing  Mirror  covers  the  stage.  The  Analyzer  is 
a  Nicol’s  Prism  6-millimeter  aperture  mounted  in  brass  tube.  It  is  provided  with  pointer  and 
graduated  arc.  An  improved  Holder  is  provided  for  specimens  to  be  studied . $8.00 


ICELAND  SPAR.  Iceland  Spar  is  a  crystallized  mineral  which  produces  two  refracted  beams  of  light  from 
one  incident  ray. 

Iceland  Spar  comes  in  many  forms,  all  of  which  may  be  reduced  by  cleavage  to  the  rhombohedron.  This  min¬ 
eral  comes  in  many  grades  of  purity  and  clarity,  although  the  double  refraction  can  be  shown  by  the  quality  readily 
obtained,  and  as  generally  listed.  We  recommend  our  No.  78-76. 


78-76  ICELAND  SPAR,  best  quality,  recommended  for  its  remarkable  purity  and  clarity . $0.75 

78-76  ICELAND  SPAR,  large  size,  medium  quality . 30 

78-77  ICELAND  SPAR,  ordinary  quality . 25 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


275 


No.  78-85 


Nos.  78-96  to  78-100 


No.  78-87 


TOURMALINE  TONGS.  Tourmaline  is  a  uni-axial  negative  crystal  in  the  form  of  a  regular  hexagonal  prism 
from  which  only  the  “extraordinary”  ray  emerges,  while  the  “ordinary”  is  rapidly  absorbed.  It  can,  therefore, 
be  used  in  producing  a  polarizing  light.  The  optical  axis  of  tourmaline  coincides  with  the  prism  and  for  optical 
purposes  the  plate  is  cut  from  it  parallel  to  the  axis. 

In  tourmaline  tongs  used  for  illustrating  and  analyzing  polarized  light,  two  tourmaline  crystals  are  mounted 
in  discs  which  are  held  as  illustrated.  These  discs  are  each  free  to  move.  If  the  prisms  are  placed  so  that  their  axes  are 
parallel,  light  emerges  as  the  prisms  are  turned  so  that  their  axes  are  at  an  angle.  In  use,  the  crystal  to  be  studied 
under  polarized  light  is  placed  between  the  two  crystals. 

78-86  TOURMALINE  TONGS,  simple  form,  medium  size  tourmaline  prisms,  capable  of  ordinary  work  .  $2.26 

78-87  PARALLELLY  ADJUSTABLE  TOURMALINE  TONGS,  superior  quality  tourmaline  plates  with 
improved  mounting,  which  allows  of  wide  separation  of  the  plates;  also  convenient  method  of 
turning  the  tourmaline  holders . Duty  Free  11.40 


NICOL’S  PRISMS 


The  ray  of  light  incident  on  the  crystal  of  Iceland  Spar  is  split  into  two  rays,  the  “ordinary”  and  the  “extraor¬ 
dinary,”  each  of  which  travels  in  a  different  plane.  In  order  that  the  incident  ray  may  be  transmitted  in  one  plane 
it  is  necessary  to  dispose  of  either  the  “ordinary”  or  “extraordinary”  ray.  The  Nicol’s  Prism  causes  the  “ordi¬ 
nary”  ray  to  be  totally  reflected,  allowing  the  free  transmission  of  the  “extraordinary”  ray. 

These  types  of  prisms  consist  of  rhombs  of  Iceland  Spar,  each  of  which  is  obliquely  cross-cut  symmetrical  to  the 
other.  Faces  polished  and  then  luted  by  the  cement  the  index  of  refraction  of  which  is  greater  than  that  of  the 
“extraordinary”  ray.  This  cross  cut  is  of  such  an  angle  that  total  reflection  of  the  “ordinary”  ray  occurs  when 
the  incident  ray  strikes  the  luted  faces. 

Our  Nicol’s  Prisms  are  purchased  from  one  manufacturer  and  are  noted  for  their  large  polarizing  field  and  their 
exceeding  clarity.  We  have  no  hesitation  in  recommending  either  those  which  are  carried  in  stock  or  those  which 
we  list  herewith,  free  of  duty. 


78-96 

78-97 

78-100 


78-110 


NICOL’S  PRISMS,  luted  by  Canada  Balsam,  polarizing  field  of  22J^  degrees. 


a  b  c 

Aperture  .  6  7  8  millimeters 

Each  . $3.30  4.90  6.40 

- ,  same  as  above,  but  larger  aperture. 

a  b  c 

Aperture  .  15  20  25 

Each,  Duty  Free  .  .  $9.26  22.26  46.00 

NICOL’S  PRISMS,  luted  with  evaporated  linseed  oil.  Aperture  Jjf  of  length,  polarizing  field  30 
degrees. 

&  1)  c  d  6 

Length  .  21  24  27  30  45  millimeters 

Each,  Duty  Free  .  .  $6.90  7.26  9.80  14.26  37.60 

FOUCAULT’S  PRISMS.  The  Foucault’s  Prism  is  a  type  of  Nicol’s  Prism  remarkable  for  its  clarity, 


the  luting  being  a  stratum  of  air.  Polarizing  field  8  degrees. 

abed 

Aperture  .  20  25  30  35  millimeters 

Each,  Duty  Free  .  .  $7.26  14.60  24.00  29.60 


276 


L .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


OBJECTS  FOR  THE  POLARISCOPE 


No.  78-140 

78-140  UNANNEALED  (IMPERFECTLY  ANNEALED)  GLASS  SPECIMENS.  Suddenly  cooled  glass 

exhibits  double  refraction.  In  consequence  such  specimens  will  show  different  patterns  under  a 
beam  of  polarized  light. 

Set  of  eight  selected  specimens  as  above  illustrated . Duty  Free  $12.00 


SELENITE  DESIGNS  EXHIBITING  MOST  BEAUTIFUL  COLORS  IN  POLARIZED 

LIGHT 


78-163 

78-164 

78-166 

78-166 

78-167 

78-168 

78-166 

78-170 

78-172 

78-174 

78-176 

78-180 

78-181 

78-186 

78-186 

78-190 

78-196 

78-206 

78-207 

78-210 

78-211 

78-220 

78-221 

78-226 

78-226 


FOUR  SELENITE  PLATES  together  in  four  colors . 

CUBE,  three  colors . . . 

OCTAHEDRON,  four  colors . . 

STAR,  six  colors . ‘ . . 

BUTTERFLY,  most  beautiful  effects  . 

BOUQUET,  highly  recommended  for  its  many  strikingly  beautiful  colors .  Duty  Free 

UNCUT  MICA,  for  individual  adjustment,  set  of  six  plates  of  different  thicknesses . 


MICA  PLATE,  undulation,  40  millimeter  aperture . 

- ,  J4  undulation,  30  millimeter  diameter . 

- ,  undulation,  12  to  15  millimeter  diameter . . . 

MICA  PLATE,  l/2  undulation,  12  to  15  millimeter  diameter . 

MICA  COMBINATION,  after  Noremberg,  collection  of  six  pieces . Duty  Free 

- ,  after  Noremberg,  in  one  preparation . Duty  Free 

- ,  after  Reusch,  plates  crossed  under  60  degrees,  turning  right  and  left . Duty  Free 

- ,  after  Reusch,  plates  crossed  under  45  degrees . Duty  Free 

MICA  WEDGES,  two  Mica  Wedges,  eight  steps,  each  wedge  arranged,  one  to  turn  over  the  other. 

Per  pair . . Duty  Free 


MICA  WEDGES,  16  steps,  to  4  undulations,  in  form  of  the  object  bearer,  11  X  70  millimeters. 

Duty  Free 

SELENITE  PLATE,  between  two  %  undulation  mica  plates,  aperture  40  millimeters.  Duty  Free 
SELENITE  DOUBLE  PLATE,  between  two  undulation  mica  plates,  aperture  40  millimeters. 

Duty  Free 

SELENITE  AND  MICA  COMBINATION,  according  to  Wright,  magnificent  colors,  collection 

of  six  pieces . . Duty  Free 

- ,  same  as  above,  but  collection  of  eight  pieces . Duty  Free 

SELENITE  PLATE  for  examining  the  character  of  double  reflection  by  uni-axial  crystal  cuts,  40 

millimeter  aperture . Duty  Free 

SELENITE  PLATE,  same  as  above,  but  30  millimeter  diameter . Duty  Free 

SELENITE  PLATES,  in  x/i,  %  and  %  undulations,  laid  one  to  the  other,  giving  thirteen  different 

steps,  for  diffused  light . .  Duty  Free 

- ,  same  as  above,  but  for  sodium  light . Duty  Free 


$2.16 

2.70 

3.40 
5.00 

6.15 
9.50 

.90 

2.26 

1.60 

1.00 

1.00 

6.25 

7.15 

7.26 

7.40 

7.60 

6.90 

3.25 

3.76 


7.00 

9.76 

6.25 


5.00 


5.40 

5.90 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


277 


PROJECTION  APPARATUS 


It  is  probable  that  more  important  changes  and  improvements  have  been  made  during  the 
past  few  years  in  Projection  apparatus  than  in  any  other  department  of  laboratory  equipment. 

The  various  requirements  of  a  well  equipped  laboratory  are  so  numerous,  ranging  as  they  do 
from  simple  projection  to  moving  pictures,  that  it  requires  long  experience  and  critical  judg¬ 
ment  to  select  the  proper  equipment  for  any  given  laboratory. 

We  are  prepared  to  recommend  the  very  latest  and  best  types  of  projection  machines  and 
will  do  so  upon  request.  When  writing  to  us  upon  this  subject,  please  inform  us  of  the  size  of 
the  Class  Lecture  Room,  or  Auditorium,  the  size  of  the  picture  desired,  whether  or  not  electricity 
is  available  and  if  so  the  kind  and  the  voltage,  and  all  other  local  conditions  which  may  assist 
us.  We  shall  then  be  pleased  to  give  detailed  information  as  to  the  combination  which  we 
recommend. 


278 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MAGNETISM  AND  STATIC  ELECTRICITY 

MAGNETS 

Our  line  of  apparatus  illustrative  of  Magnetism  and  its  various  properties  has  been  selected  with  great  care. 
Our  magnets  are  of  the  best  quality  steel  and  will  retain  their  m  agnetism. 


80-10  LODESTONE  or  NATURAL  MAGNET.  As  suggested  by  the  name, 
this  magnet  is  a  selected  piece  of  iron  ore  having  magnetic  properties. 

It  exerts  attractive  and  repulsive  force  and  is  readily  affected  by  the 
earth’s  magnetic  power . $0.22 

80-11  LARGE  DEMONSTRATION  TABLE  LODESTONE  or  NATURAL 

MAGNET,  highest  quality . 66 

80-14  SUPPORTING  STIRRUP  FOR  LODESTONE,  used  in  illustrating  the 
action  of  the  earth’s  magnetic  force.  This  stirrup  will  contain  either 
of  the  lodestones  listed  above . 66 


Nos.  80-10  to  80-11 


S 


HORSESHOE  MAGNETS  WITH  KEEPERS 

Numbers  .  80-20  80-22  80-24  80-26  80-28 

Length,  inches  ...  2  3  4  6  8 

Each .  $0.08  0.11  0.18  0.48  1.00 

80-30  HORSESHOE  MAGNET,  special  design,  2  inches  between  poles.  Length  5M  inches,  poles  %  X  M 

inch . $0.35 

80-32  U-SHAPED  MAGNET,  after  Fuller  and  Brownlee  (Experiment  86)  . 40 

80-36  COMPOUND  HORSESHOE  MAGNET,  demonstrating  the  intensified  magnetic  force  derived  by 

the  combination  of  more  than  a  single  magnet.  Two  magnets  firmly  clamped  together  with  keeper  .  1.70 

80-37  EIGHT-INCH  COMPOUND  HORSESHOE  MAGNET,  consisting  of  four  eight-inch  single  magnets 

firmly  clamped  together.  With  keeper .  6.40 

BAR  MAGNETS,  finest  quality  steel,  excellent  retentive  quality,  neatly  polished. 

Numbers  ....  80-66  80-67  80-69  80-61 

Size,  inches  ....  2X^XM  6  X  M  X  M  8  X  MX  M  12  X  1  X  M 
Price  .  .Each,  $0.18  Per  Doz.  1.60  0.20  0.30  0.60 

80-70  BAR  MAGNETS,  consisting  of  a  pair  of  6-inch  Bar  Magnets  in  neat  wooden  box,  with  keepers  .  .60 

80-80  ROUND  BAR  MAGNET,  excellent  quality  polished  steel,  length  6  inches,  diameter  %  inch  ...  .26 

80-86  BREAKING  MAGNET,  illustrating  the  fact  that  both  polarities  of  magnetism  are  present  at  all  parts 
of  the  bar,  and  are  not  merely  at  the  ends. 

This  Magnet  is  6  inches  long  by  M  inch  square,  weakened  at  various  points  to  facilitate  in  the 
breaking . 22 

80-87  GLASS  TUBE  and  STEEL  FILINGS,  illustrating  the  molecular  character  of  magnetism. 

This  consists  of  a  small  glass  tube  filled  with  washed  steel  filings.  If  the  filings  are  magnetized  by  the 
approach  of  a  bar  magnet,  each  small  filing  will  attain  the  characteristics  of  a  magnet,  attracting 
and  repelling  adjacent  filings,  so  that  they  will  all  cluster  together  to  form  a  solid  mass.  This  con¬ 
dition  may  be  destroyed  by  violently  shaking  the  tube,  thus  destroying  the  magnetism . 30 

80-90  MAGNETIZED  STEEL  DISC,  useful  in  destroying  the  conception  of  the  students  that  magnets  must 
be  in  the  form  of  rods  or  bars. 

This  disc  is  2  inches  in  diameter  and  has  two  distinct  magnetic  poles 


.66 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


279 


80-100  HARDENED  STEEL  RODS  (KNITTING  NEEDLES),  about  %  inch  diameter  by  8  inches  long. 

These  steel  rods  are  useful  in  the  study  of  Breaking  Magnets.  Per  set  of  four . 

80-102  LARGE  DARNING  NEEDLES.  Package  of  25  needles . 

80-106  SOFT  IRON  BAR,  for  illustrating  the  action  of  the  earth  on  magnetic  substances;  may  be  used  also 
to  illustrate  the  formation  of  magnets  by  enclosing  in  a  solenoid  through  which  passes  a  current 
of  electricity. 

This  bar  is  of  the  best  quality  of  soft  Norway  iron  and  measures  6  X  ^  X  . 

80-106  SOFT  NORWAY  IRON  ROD,  20  inches  long  by  inch  diameter,  for  studying  the  action  of  the  earth 
on  magnetic  substances.  When  this  bar  is  held  in  the  magnetic  meridian  parallel  to  the  inclination, 
feeble  magnetic  polarity  is  at  once  noticeable  in  the  bar,  the  lower  extremity  being  the  North  Pole, 
as  may  be  demonstrated  by  testing  with  a  small  magnetic  needle.  This  magnetism  is  unstable,  as 
may  be  demonstrated  by  inverting  the  bar.  The  magnetic  polarity,  however,  may  be  made  some¬ 
what  more  stable  by  imparting  to  the  bar  a  certain  amount  of  coercive  force  by  giving  it  several 
sharp  blows  with  a  hammer.  This  coercive  force  is,  of  course,  very  small,  and  after  a  time  the 
magnetism  entirely  disappears . 

89-107  SOFT  IRON  HORSESHOE  CORE,  after  Millikan,  Gale  and  Bishop  (Experiment  30) . 

80-108  CYLINDRICAL  IRON  ARMATURE,  after  Turner  and  Hersey  (Experiment  E011) . 

80-109  TWO-PART  IRON  ARMATURE,  after  Turner  and  Hersey  (Experiment  E011) . 

80-110  NICKEL  STRIP  for  illustrating  that  other  substances  than  iron  have  magnetic  properties. 

This  strip  is  4  X  ]/i  inch . 

80-116  MAGNETIC  SCREENS  for  illustrating  magnetic  transparency,  consisting  of  a  set  of  six  screens  of 
different  substances,  some  paramagnetic,  others  diamagnetic  .......  Per  set  of  six 

80-117  PARAMAGNETIC  AND  DIAMAGNETIC  SUBSTANCES . Package 

80-120  MAGNET  STIRRUP,  for  the  study  of  magnetic  action  in  a  suspended  bar  magnet. 

This  consists  of  a  wire  stirrup  with  a  device  for  holding  magnets  and  also  for  attaching  to  a  support 
by  a  string . 


$0.05 

.06 


.20 


.40 

.10 

.04 


.04 


.30 


.70 

.40 


.10 


No.  80-123 


No.  80-160 


No.  80-160 


80-123  BLACK’S  MAGNET  and  FRICTION  ROD  SUPPORT.  The  magnet  or  friction  rod  carrier  is  con¬ 
structed  of  very  light  weight  metal  and  when  balanced  as  illustrated  on  the  hardened  steel  sup¬ 
porting  needle,  moves  with  very  little  inertia.  A  magnet  or  friction  rod  resting  on  this  carrier,  there¬ 
fore,  reacts  readily  to  other  magnetic  or  static  charges . $1.60 

80-160  MOLECULAR  MAGNET  MODEL  for  explaining  the  distribution  of  Magnetism  in  magnetic  rods. 

This  apparatus  consists  of  twenty-four  small  magnets  about  2  centimeters  long,  each  supported  on  a 
point  and  all  placed  as  illustrated,  on  an  insulated  board.  These  magnets  will  arrange  themselves 
so  that  the  like  poles  all  point  in  one  direction.  If,  however,  the  pole  of  a  strong  Bar  Magnet  be 
presented  to  one  end,  the  needles  will  be  immediately  deflected. 

Set  of  twenty-four,  mounted  as  illustrated . Duty  Free  9.26 

80-166  FLOATING  MAGNETS  for  illustrating  the  attraction  and  repulsion  of  magnetic  poles. 

This  apparatus  consists  of  a  set  of  six  small  magnets  each  on  an  individual  mount  that  will  float  in 

water .  Per  set  of  six  .20 


80-160  SUPPORTING  BOARD  for  use  with  a  magnet  and  tracing  paper  for  forming  a  tracing  of  the  lines 
of  force  of  a  magnet. 

This  board,  as  shown  in  the  illustration,  has  a  groove  in  the  middle  into  which  the  magnet  is  placed, 
bringing  the  surface  of  the  magnet  flush  with  the  top  of  the  board. 

In  use,  a  sheet  of  blueprint  paper  is  pinned  to  the  board  over  the  magnet.  Iron  filings,  sifted  over  this 

sheet,  will  arrange  themselves  in  the  lines  of  force  of  the  magnet .  .46 

80-166  MAGNET  SUPPORTS.  These  supports  consist  of  short  strips  of  wood  inch  cross-section.  They 
are  designed  for  use  with  magnets  No.  80-66.  The  blueprint  paper  is  placed  on  these  wooden 
supports . Per  Pair  .06 

80-167  SPECIAL  MAGNET  BLOCK,  after  Turner  and  Hersey  (Experiment  E011) .  .04 

80-170  GLASS  PLATES  (6X6  inches),  for  use  in  mapping  magnetic  fields  of  force. 

These  plates  may  be  used  to  advantage  with  No.  80-165  Supporting  Strips,  and  No.  80-56  Bar 
Magnet . ' . Each  .10 


28o 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


80-180  IRON  FILINGS  for  mapping  magnetic  lines  of  force.  Selected,  fine,  soft  iron  filings. 

Per  x/i  lb.  carton  $0.10 
Per  lb.  in  bulk  .20 

80-186  FILINGS  SIFTER  for  evenly  distributing  filings  over  a  tracing  surface .  .16 

80-187  CHEESE  CLOTH  BAG . 10 

80-190  BLUEPRINT  PAPER  for  permanently  recording  a  magnetic  field  of  force  of  a  bar  magnet,  as  indi¬ 
cated  by  iron  filings.  Size,  8H  X  10 Yi  inches.  Per  light-proof,  sealed  package  of  100  sheets  .  .  1.26 

80-200  DIRECT  BLACKPRINT  PAPER,  more  desirable  than  blueprint  paper  as  it  gives  a  black  line  on 
white  ground. 

This  paper  is  treated  like  ordinary  blueprint  paper,  except  that  the  print  should  be  left  in  the  bath 

from  10  to  15  minutes . Per  10-yard  roll,  medium  weight,  30  inches  wide  .  2.75 

80-225  LINES  OF  FORCE  APPARATUS,  after  Toepler,  for  show¬ 
ing  the  magnetic  curves  between  the  poles  of  an  electro¬ 
magnet.  Excellent  in  projection  work. 

This  apparatus  consists  of  a  glass  trough  placed  between 
the  poles  of  an  electro-magnet.  This  trough,  in  use,  is  filled 
with  glycerine  in  which  fine  iron  filings  have  been  pre¬ 
viously  mixed.  When  a  current  is  allowed  to  pass  through 
the  electro-magnet,  the  small  particles  of  iron  will  arrange 
themselves  in  magnetic  curves.  This  instrument  forms 
an  instructive  and  interesting  piece  of  apparatus  .... 


$7.80  No.  80-225 


80-230  MAGNETIC  LINES  OF  FORCE  APPARATUS  for  use  with  a  Vertical  Projector  in  showing  on  a 
screen  the  lines  of  force  about  a  current. 

This  apparatus  consists  of  a  set  of  six  slides,  each  slide  being  a  glass  plate  set  in  a  wooden  frame. 
Through  holes  bored  in  the  glass,  various  forms  of  wire  are  set.  In  projection  work,  this  set  will 
be  found  invaluable . Per  set  of  six  slides  $9.75 


No.  80-232 

80-232  MAGNETIC  LINES  OF  FORCE  APPARATUS  for  use  with  a  Vertical  Projector  in  showing  on  a 
screen  the  lines  of  force  about  a  magnet. 

This  apparatus,  similar  to  Set  No.  80-230,  consists  of  a  set  of  six  slides,  each  slide  consisting  of  two 
plates  between  which  are  placed  thin  steel  magnets  of  various  forms  and  differently  arranged  as 
illustrated . Per  set  of  six  slides  $2.50 

80-236  MAGNETIC  LINES  OF  FORCE  SLIDES,  for  illustrating  on  a  screen  the  fields  of  force  shown  by 
iron  filings. 

These  slides  are  direct  photographs  and  are  selected  from  our  Miller  Collection.  The  set  consists  of 
five  slides  illustrating  the  field  of:  (1)  Single  Bar  Magnet;  (2)  Two  Bar  Magnets,  Unlike  Poles; 

(3)  Two  Bar  Magnets,  like  Poles;  (4)  Two  Bar  Magnets  at  Right  Angles;  (5)  Ring  Magnets. 

Per  set  of  five  2.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


281 


80-260 


80-262 


80-263 


MAGNETOMETERS 


Nos.  80-260  and  80-263 


MAGNETOMETER,  after  Millikan  and  Mills’  “Electricity,  Sound  and  Light”  (Experiment  2), 
for  determining  the  magnetic  moment  (M)  and  horizontal  component  of  the  earth’s  magnetic 
field  (H),  by  first  determining  the  relation  M/H  and  MH. 

This  magnetometer  is  carefully  designed  to  do  accurate  work.  The  suspension  system  consists 
of  five  small  magnets,  cemented  to  the  back  of  an  optically  plane  glass  mirror.  This  system 
is  held  by  a  silk  fibre  suspended  from  the  graduated  torsion  head.  The  brass  housing  is  so  mounted 
on  the  tripod  that  it  may  be  turned  about  a  vertical  axis.  The  outer  wall  of  this  housing,  with 
clear,  flat  glass  window,  may  readily  be  removed  as  illustrated,  without  disturbing  the  suspension 
system. 

Magnetometer  complete  with  Suspension  System . 


MAGNET  AND  METER  ROD  SUPPORTS.  In  determining  the  value  M/H  a  bar  magnet  of 
a  size  determined  by  the  diameter  of  the  lower  part  of  the  housing  and  an  appropriate  support 
for  the  same,  east  and  west  of  the  suspended  system,  are  needed.  These  supports  utilize  the 
standard  meter  stick  found  in  all  laboratories.  The  meter  rod  is  supported  by  special  brass  castings; 
the  magnet  support  is  designed  to  rest  on  the  meter  stick  wherever  desired.  An  index  on  the 
magnet  support  enables  one  to  make  an  accurate  reading  of  the  distance  of  the  magnet  from 
the  magnetometer  mirror. 

One  pair  special  brass  Meter  Rod  Supports  and  Magnet  Holder . 


INERTIA  ACCESSORIES  for  use  with  above  Magnetometer,  in  determining  the  moment  of  inertia 
of  the  magnet  of  No.  80-260. 

This  system  consists  of  a  stirrup  to  which  is  attached  a  plane  mirror  and  which  is  designed  to  hold  the 
magnet.  That  results  may  be  checked,  a  brass  inertia  ring  is  supplied. 

Inertia  Ring,  Magnet,  and  Stirrup  with  Attached  Mirror . 


$18.00 


1.40 


3.16 


282 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  80-265 


No.  80-300 


f 


80-265  SPRING  MAGNETOMETER,  after  Stewart  &  Gee’s  “Elementary  Practical  Physics,”  Lesson  XIII, 
for  determining  the  distribution  of  magnetism  along  a  bar  magnet. 

In  use,  the  zero  point  is  obtained  by  substituting  for  the  magnet  a  piece  of  wood  of  the  same  dimen¬ 
sions,  then  turning  the  milled  head  until  the  soft  iron  piece  just  touches  the  surface  of  the  wood. 

Place  the  magnet  in  position,  and  determine  the  number  of  divisions  through  which  the  milled  head 
must  be  turned,  to  detach  the  iron  piece.  Readings  should  always  be  made  from  the  middle  of 
the  magnet  toward  each  end.  From  a  number  of  such  readings,  it  will  be  noted  that  the  magnetic 
strength  is  directly  proportional  to  the  distance  from  the  center. 

Complete  with  Special  Magnet  and  similar  wooden  strip . $7.60 

80-270  DEFLECTION  MAGNETOMETER  for  comparing  the  strength  of  the  poles  of  a  bar  magnet. 

The  apparatus  consists  of  a  polished  mahogany  base  board  to  the  surface  of  which  is  fastened  a 
meter  rod.  Midway  between  the  ends  of  this  rod  a  delicate  magnetic  needle  is  placed,  with  the 
50  centimeter  division  of  the  rod  directly  under  the  supporting  pivot  of  the  needle. 

Complete  with  Magnetic  Needle  and  Bar  Magnet .  2.26 

80-280  MAGNETOSCOPE,  after  Chute’s  “Physical  Laboratory  Manual,”  Problems  104  to  106,  for  measur¬ 
ing  relative  magnetic  transparencies  of  various  substances;  for  comparing  strength  of  poles  and 
determining  distribution  of  magnetism  along  a  bar  magnet. 

This  simple  instrument,  capable  of  relatively  exact  measurements,  consists  of  a  heavy  jar  of  special 
design,  mounted  on  a  wooden  pedestal.  A  strongly  magnetized  permanent  magnet  is  suspended 
through  a  stopper  plug .  .96 

80-300  MAGNETIC  POLE  ROTATION  APPARATUS  for  demonstrating  the  tendency  of  a  current  and  a 

magnet  pole  to  rotate  about  each  other. 

The  apparatus  consists  of  a  jewel-mounted  magnet  supported  so  that  the  current  passes  along  half 
the  length  of  the  magnet  and  is  carried  away  at  the  middle.  The  magnet  is  supported  at  its  center 
on  a  fine  point  on  top  of  a  post.  The  current  is  brought  to  a  mercury  cup  fitted  to  the  magnet,  and 
a  bent  copper  wire  attached  to  this  cup  dips  into  an  annular  mercury  cup,  whence  it  is  carried  away 
by  the  upright  support  to  which  the  cup  is  attached.  When  a  strong  current  is  passing  (3f$ 
amperes  at  7  volts  pressure,  at  least)  one  pole  will  rotate  steadily.  By  reversing  the  direction  of 
the  current,  the  direction  of  the  rotation  is  reversed. 

Complete  as  illustrated .  4.36 

80-116  MAGNETIC  SCREENS,  set  of  six  screens  of  different  substances,  some  paramagnetic,  others  dia¬ 
magnetic  . 70 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


283 


80-306 


80-310 


80-326 


No.  80-306  No.  80-310 

PARALLEL  CURRENT  APPARATUS  for  illustrating  mutual  actions  of  parallel  currents.  The 
design  consists  of  an  insulated  stand  to  the  head  of  which  are  attached  binding  posts  in  electrical 
connection  with  two  bent  copper  wires.  To  these  bent  wires  are  suspended  two  straight  copper 
rods  cut  to  lengths  that  will  allow  their  free  ends  to  extend  within  the  mercury  well  set  in  the  base. 

In  use  it  is  always  best  to  amalgamate  the  ends  of  these  copper  rods.  Success  of  the  experiment 
depends  also  upon  allowing  the  rods  to  just  make  contact  with  the  surface  of  the  mercury.  Parallel 
currents  flowing  in  the  same  direction  may  be  secured  by  connecting  both  binding  posts  with  one 
pole  of  the  battery;  the  other  pole  should  be  connected  to  a  binding  post  (not  shown  in  illustration) 
fastened  to  the  base  and  in  electrical  connection  with  the  mercury  well. 

Parallel  currents  running  in  opposite  directions  may  be  obtained  by  simply  connecting  the  battery 
terminals  and  the  binding  posts,  at  the  top. 

In  the  first  case,  repulsion  of  the  wires  will  be  noted;  in  the  second  attraction . 


VIBRATING  SPIRAL  APPARATUS  for  illustrating  mutual  action  of  parallel  currents. 

The  apparatus  consists  of  a  stand  with  upright.  In  the  base  is  set  a  mercury  well  in  electrical  con¬ 
nection  with  a  binding  post.  A  horizontal  rod  set  into  the  upright  near  the  top  is  provided  at  one 
end  with  a  binding  post  and  at  the  other  with  a  binding  screw,  the  latter  designed  to  support  one  end 
of  a  loose  copper  wire  spiral.  The  other  end  of  this  spiral  extends  within  the  mercury  well.  In  use, 
this  end  should  be  regulated  to  just  touch  the  surface  of  the  mercury.  When  a  current  is  allowed 
to  pass  through  the  spiral,  there  is  an  attraction  between  the  convolutions,  causing  the  lower  end 
of  the  spiral  to  break  the  electrical  connection  with  the  mercury.  The  weight  of  the  spiral  then 
causes  contact  again,  which,  in  turn,  sets  up  attraction  of  the  convolutions.  Continual  making  and 
breaking  contact  with  the  mercury  causes  this  spiral  to  vibrate  up  and  down . 


No.  80-326 


MAGNETIC  DISTRIBUTION  APPARATUS,  after  Stewart  &  Gee’s  “Elementary  Practical  Phys¬ 
ics,”  Lesson  LXXII,  for  studying  the  distribution  of  magnetism  along  a  soft  iron  bar  magnetized 
by  induced  currents  from  a  magnetizing  helix. 

This  apparatus  consists  of  a  long,  soft,  Norway  iron  bar,  mounted  on  supports  as  illustrated.  At 
the  end  are  two  short  pieces  of  brass  of  the  same  diameter  as  the  iron  rod,  permitting  the  whole 
length  of  the  iron  rod  to  be  brought  under  experimentation.  For  magnetizing  purposes  a  test  coil 
which  may  be  clamped  to  any  part  of  the  bar,  is  supplied.  A  small  reel  wound  with  fine  wire  is 
employed  as  the  induction  coil.  The  range  of  play  and  the  position  of  the  test  coil  is  determined  by 
two  brass  guides  between  which  this  reel  is  placed.  The  guide  and  reel  are  each  provided  with 
screws  for  clamping-  to  the  rod. 

Complete  as  illustrated . 


$1.86 


1.35 


$9.65 


284 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  ) 


E  QUIPOTENTIAL  APPARATUS 


No.  80-350 


80-360  E QUIPOTENTIAL  DETERMINATION  APPARATUS,  after  Millikan  &  Mills’  “Electricity,  Sound, 
and  Light”  (Experiment  1),  for  mapping  the  equipotential  surface  of  an  electrical  field  and  drawing 
the  force  lines. 

The  apparatus  consists  of  a  field  tray  with  glass  bottom,  through  which  may  be  seen  a  sheet  of  co¬ 
ordinate  paper.  This  tray  is  an  improved  design  by  C.  H.  Andrews,  South  High  School,  Worcester, 
Mass.  With  this  design  it  is  impossible  for  the  salt  solution  to  come  into  contact  with  the  paper, 
and  the  whole  tray  may  be  thoroughly  cleaned  without  removing  the  glass  plate.  It  has  the  further 
advantage,  also,  of  facilitating  the  replacing  of  broken  plates.  Three  bent  wires,  each  with  weighted 
support  and  binding  post,  are  provided.  Two  of  these  are  maintained  at  points  of  different  poten¬ 
tials  and  about  which  it  is  desired  to  find  equal  potential  lines  which  lie  in  one  plane.  A  constantly 
varying  potential  difference  is  secured  by  connecting  these  points  to  the  secondary  of  an  induction 
coil.  A  fourth  bent  wire  with  insulating  handle  and  binding  post  is  used  with  the  third  point  as 
illustrated  in  locating  the  points  of  equipotential.  The  fourth  point  may  then  be  considered  the 
equipotential  seeker. 

In  use,  the  bottom  of  the  tray  is  covered  with  a  solution  of  ammonium  chloride  or  any  convenient 
salt.  The  bent  wires  then  are  located  as-illustrated,  two  connected  to  the  secondary  of  an  induc¬ 
tion  coil  the  primary  of  which  is  connected  to  a  dry  cell,  the  third  and  the  equipotential  seeker  are 
connected  to  telephone  receiver.  By  adjusting  the  position  of  the  third  wire  to  various  points  in 
the  plane  of  the  liquid,  points  of  equipotential  for  these  different  points  may  be  located  by  means 
of  the  seeker.  These  points  will  be  found  when  there  is  no  “buzzing”  in  the  telephone  receiver. 
Results  may  be  transferred  to  a  sheet  of  co-ordinate  paper  and  equipotential  lines  and  the  lines  of 
flow  drawn. 

Complete  apparatus  consists  of  the  Field  Tray  and  the  four  bent  wires,  three  with  weighted  supports 


and  binding  posts,  the  fourth  with  insulating  handle.  Complete . $6.00 

80-361  FIELD  TRAY,  improved  design  by  Andrews .  4.00 

80-362  BENT  WIRE,  WITH  WEIGHTED  SUPPORT  AND  BINDING  POST  .  .  • . Each  .60 

80-363  BENT  WIRE,  WITH  INSULATING  HANDLE  AND  BINDING  POST . Each  .60 

19-67  CO-ORDINATE  PAPER,  ruled  6X8  inches  on  sheet  8}^  X  lOj^,  millimeter  ruling,  heavy  centi¬ 
meter  divisions . v . Per  100  sheets  .60 

80-366  INDUCTION  COIL,  small  size  with  modified  hammer,  especially  adapted  to  this  work .  4.00 

98-100  BIPOLAR  DISSECTEBLE  TELEPHONE  RECEIVER,  as  above  illustrated .  1.46 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


285 


TERRESTRIAL  MAGNETISM 

MAGNETIC  NEEDLES 


81-10  MAGNETIC  NEEDLE,  brass  capped,  agate  bearing,  neat  stand  with  pinion,  needle  6  inches  long  .  .  $0.90 


81-12  - ,  same  as  above,  brass  capped  only .  _60 

81-16  ASTATIC  NEEDLE,  improved  design,  brass  caps,  neat  stand  with  pinion,  needle  6  inches  long, 

system  mounted  so  that  like  or  unlike  poles  may  be  opposite  each  other .  1.40 


No.  81-60  No.  81-66 

81-60  STUDENTS’  DEMONSTRATION  DIP  NEEDLE,  as  designed 
by  W.  R.  Pyle  of  Morris  High  School,  New  York  City. 

This  instrument  consists  of  a  stand  on  which  may  be  supported 
the  dipping  system.  It  is  intended  that  this  system  should  be 
magnetized  by  the  student.  For  this  purpose,  there  are  sup¬ 
plied  four  steel  rods  inch  diameter,  about  8  inches  long. 

Our  dipping  system  consists  of  a  device  whereby  one  of  these 
steel  rods  may  be  mounted  and  balanced  unmagnetized  and 
damped  in  the  system.  The  needle  is  then  magnetized  by 
stroking  from  the  middle  toward  each  end  with  a  strong  bar 
magnet.  The  dip,  then,  may  be  taken  and  noted.  This  little 
instrument  has  found  ready  favor  in  many  schools  and  is  highly 
recommended  for  its  didactic  features . $0.96 


No.  81-60 


81-66  DIPPING  NEEDLE  for  showing  magnetic  dip. 

This  design  consists  of  a  standard  on  which  is  mounted  a  forked  casting.  In  this  forked  casting  is 
mounted,  in  pivotal  bearings,  a  carefully  magnetized  and  balanced  needle.  A  graduated  arc,  also 
mounted  in  this  forked  casting,  gives  the  magnetic  dip . $3.30 

81-60  DIP  NEEDLE.  This  instrument,  of  the  highest  quality,  and  capable  of  exact  determinations,  con¬ 
sists  of  a  horizontal  circle  mounted  on  a  tripod  with  leveling  screws.  Above  the  circle  is  a  pillar 
movable  about  a  vertical  axis  and  ending  above  in  a  forked  stirrup,  designed  to  support  the  dip 
system.  This  system  consists  of  a  silvered-metal  engine-divided  circle  fitted  between  brass  stirrups 
which  act  as  a  support  for  the  needle.  Set  screws  fitted  with  cones  and  lock  nuts  carry  the  hardened 
steel  axis  of  a  delicately  balanced  needle.  The  sensitive  spirit  level  mounted  on  the  pillar  facili¬ 
tates  leveling . Duty  Free  17.60 


286 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


49-27 


81-76 

81-76 

81-77 

81-78 

81-86 

81-87 

81-96 

81-100 

81-101 


COMPASSES 


No.  49-27 


MINER’S  COMPASS  or  DIPPING  NEEDLE,  a  serviceable  guide  to  the  location  of  magnetic  iron 
ore. 

In  this  instrument  the  magnetic  needle  is  horizontally  balanced  on  an  axis  within  a  graduated  circle 
and  in  which  the  needle  will  be  found  to  assume  a  position  inclined  to  the  horizon.  When  used 
for  tracing  ore,  the  observer  should  hold  the  ring  in  his  hand  and  keep  the  needle  north  and  south, 
standing  with  his  face  to  the  west.  The  inclination  of  the  needle  as  read  on  the  graduated  scale 
will  show  the  dip.  If  the  compass  is  held  horizontally,  it  serves  as  an  ordinary  compass.  This 
compass  is  handsomely  finished  with  raised  silvered-metal  graduated  scale,  and  is  inches  in 
diameter.  It  is  provided  with  a  brass  cap  cover  and  is  enclosed  in  a  neat  plush-lined  box  ....  $11.00 


Nos.  81-76  to  81-78 


Nos.  81-86  to  81-87 


No.  81-96 


MAGNETIC  COMPASS,  consisting  of  small,  delicately  balanced  needle  mounted  in  polished  brass 

case,  with  card  dial,  diameter  12  millimeters . Per  Dozen  $1.40 

MAGNETIC  COMPASS,  similar  to  above,  but  25  millimeters  diameter,  and  supplied  with  ring  .  .  .18 

- ,  same  as  above,  but  35  millimeters  diameter  .  • .  .26 

- ,  same  as  above,  but  50  millimeters  diameter .  .33 


MAGNETIC  COMPASS,  superior  quality,  raised  metal  dial  with 
full  circle  divisions,  delicately  balanced  needle  with  brass-capped 
agate  bearing  enclosed  in  polished  brass  case,  with  stop  for  needle, 


diameter  30  millimeters .  $1.06 

- ,  same  as  above,  but  50  millimeters  diameter .  1.30 

MAGNETIC  COMPASS,  raised  metal  dial,  with  full  circle  divi¬ 
sions,  agate  cap  needle,  with  37-millimeter  aluminum  pointer, 
enclosed  in  polished  brass  case,  with  stop  for  needle,  diameter 
50  millimeters .  1.66 

MAGNETIC  POCKET  COMPASS,  card  dial,  full  circle  divisions 
with  cardinal  points,  needle  with  brass-capped  bearing  with  stop, 
inside  a  polished  mahogany  box  with  hinged  cover,  diameter 
2  Yi  inches .  1.26 


— ,  similar  to  above,  but  silvered-dial  and  raised  ring,  needle  with 
brass-capped  agate  bearing .  3.00 


No.  81-100 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


287 


No.  81-126 


No.  81-130 


81-125  WATCH  CASE  SIGHT  COMPASS,  234  inches  in  diameter,  excellent  quality  with  full  circle  divi¬ 
sions  on  raised  dial.  Nicely  balanced  needle,  134  inches  long,  with  agate  bearing.  Providedjwith 
folding  sights.  Spring  cover . . . $6.60 


81-130  BRIDGE  SIGHT  CLINOMETER  COMPASS,  for  use  both  as  a  clinometer  and  as  a  sight  compass. 

This  useful  instrument  is  constructed  to  fulfill  the  office  of  both  clinometer  and  sight  compass.  The 
sights  are  made  in  the  form  of  a  bridge  and  can  be  turned  on  their  pivots  at  right  angles. 

The  needle  of  this  compass  is  a  hardened  and  tempered  edge  bar  with  needle  jeweled  center.  It  is 

mounted  within  a  three-inch  bronze  case  provided  with  a  silvered-metal  dial .  7.60 


81-140  MARINE  COMPASS,  —  a  compass  in  which  the 
moving  system  is  floated  in  alcohol. 

This  is  a  high-grade  instrument  5  inches  in  diam¬ 
eter.  The  moving  system  floating  in  alcohol  is 
contained  in  a  compensating  chamber.  It  has 
a  standard  marine  compass  dial  with  line  sights. 

The  instrument  is  furnished  in  a  neat  mahogany 
case  . 11.60 


No.  81-140 


49-26  SUN  DIAL  AND  COMPASS.  This  little  instrument,  2 
inches  in  diameter,  combines  features  of  both  compass 
and  sun  dial.  It  is  a  pocket  compass  with  raised  dial 
with  distinct  divisions  and  figures,  and  agate  center 
needle.  As  a  sun  dial,  it  is  provided  with  distinct  hour 
lines  and  may  be  readily  set  to  any  latitude.  Case  is 
nickel-plated  and  provided  with  hinged  cover. 

Duty  Free  $6.76 


No.  49-26 


288 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


UNIVERSAL  INCLINATION  EARTH  INDUCTOR 


No.  81-166 


81-166  UNIVERSAL  INCLINATION  EARTH  INDUCTOR  for  exact  study  of  the  magnetic  moment  of  the 

earth’s  pole. 

This  improved  design  consists  of  a  substantial  base  with  uprights  to  which  is  swiveled  a  frame  carry¬ 
ing  a  ring.  The  frame  carrying  the  coil  may  be  inclined  to  any  angle  within  180  degrees,  the 
inclination  being  indicated  by  a  pointer  moving  before  a  graduated  arc.  The  ring  has  a  groove 
in  which  are  coiled  about  1,000  turns  double  silk-covered  wire.  The  leads  of  this  wire  are  heavily 
insulated  and  the  ends  brought  to  binding  posts  shown  on  top  of  the  frame.  A  positive  throw 
is  secured  by  a  simple  spring  device  shown  at  the  bottom  of  the  frame.  This  device,  when  set  for 
use,  is  held  by  a  projecting  rod  acting  against  the  spring  giving  to  it  a  tension.  A  release  and  stop¬ 
ping  device,  actuated  by  one  button,  gives  to  the  ring  a  definite  rotation  through  180  degrees.  This 
inductor  is  carefully  made  and  must  not  be  confused  with  those  at  a  lower  price  on  the  market. 
Our  mounting  is  of  the  most  substantial  construction,  well  finished,  making  the  instrument  not 
only  of  scientific  value,  but  one  in  which  any  laboratory  will  take  pride. 

FEATURES: 

1.  Universal  inclination  in  two  planes. 

2.  Gimbal  mounting  for  varying  the  angle  of  inclination. 

3.  Graduated  arc  and  pointer  for  easily  determining  the  same. 

4.  Positive  spring  device  for  securing  a  definite  rotation  through  180  degrees. 

5.  A  release  and  stopping  device  actuated  by  one  button. 

To  facilitate  in  determining  the  constant  of  the  instrument  the  B.  &  S.  Gauge  No.  of  wire,  the  inner 
and  outer  diameter  of  the  coil,  the  number  of  turns  in  the  coil  and  the  resistance  are  all  perma¬ 
nently  recorded  on  the  instrument . 


$19.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


289 


GENERATION  OF  STATIC  ELECTRICITY 

FRICTIONAL  ELECTRICITY  ACCESSORIES 


In  listing  our  line  of  Frictional  Electricity  Accessories,  we  desire  to  state  that  we  use  only  the  purest  materials 
which,  from  our  experimentation,  have  proved  most  satisfactory.  Results,  therefore,  are  assured. 


‘  "SI 

Nos.  82-10  to  82-65 


82-10 

82-16 

82-20 

82-25 

82-30 

82-35 

82-40 

82-60 

82-56 

82-67 

82-60 

82-66 


82-75 


82-77 


AMBER  SPECIMEN,  illustrating  the  power  of  amber  in  attracting  light  bodies,  when  rubbed  with 

silk  . $0.96 

FRICTION  ROD  OF  GLASS,  12  X  H  inch,  developing  a  positive  charge  when  rubbed  with  silk,  nega¬ 
tive  when  rubbed^with  catskin  or  flannel .  .18 

GLASS  FRICTION  ROD,  one-half  ground,  other  half  polished,  developing  both  positive  and  negative 
charges  regardless  of  the  “rubber” . .36 

VULCANITE  FRICTION  ROD,  developing  a  negative  charge  when  rubbed  by  catskin,  flannel,  or 

silk  . 38 

WAX  FRICTION  ROD  (sealing  wax),  developing  a  negative  charge  when  rubbed  by  catskin,  flannel, 

or  silk .  .10 

CELLULOID  STRIP,  12  inches  long,  developing  a  negative  charge  when  rubbed  by  catskin,  flannel, 

or  silk .  .18 

FRICTION  ROD,  HALF  GLASS,  HALF  BRASS,  illustrating  rapid  conduction  of  charge  from  a 

conductor  .  .95 

SILK  EXCITING  PAD . 40 

FLANNEL  EXCITING  PAD . 25 

FLANNEL  CAP  WITH  ATTACHED  SILK  CORDS,  after  Millikan  and  Gale,  Figure  228  .  .  .  .15 

CATSKIN,  small  size,  whole  skin .  .75 

CATSKIN,  large  size,  whole  skin .  1.25 


No.  82-76 


CHARGING  ROD.  This  charging  rod  has  been  designed  in  order  to  provide  a  simple  and  certain 
means  for  charging  electroscopes.  The  charges  are  produced  by  the  friction  between  a  piece  of 
flannel  and  a  resinous  rod.  The  whole  is  surrounded  by  a  brass  case  which  acts  as  a  guide  for  the 
movable  flannel  ring.  The  rod  can  be  used  to  produce  either  positive  or  negative  charges  ....  $6.50 

THE  IMPROVED  POTENTIAL  BAR.  This  bar  is  designed  to  maintain  a  constant  potential  dif¬ 
ference  of  1,000  volts,  mounted  in  form  for  convenient  and  satisfactory  use  with  Electroscopes, 
Electrometers,  Leyden  Jars  and  other  high  potential  electrical  instruments.  This  is  undoubtedly 
the  most  valuable  single  instrument  obtainable  for  the  study  of  electrostatic  phenomena.  Enables 
the  instructor  to  carry  on  satisfactory  lecture  table  demonstrations  in  static  electricity  regardless 
of  atmospheric  conditions .  9-60 


290 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ELECTROPHORUS 


82-110  RITCHIE’S  LECTURE  TABLE  ELECTROPHORUS  for  generation  of  static  charges  by  the  prin¬ 
ciple  of  influence.  The  plate  of  this  electrophorus  is  12  inches  in  diameter,  constructed  of  a 
special  high  quality  electro-static  rubber  mounted  in  a  finished  metal  base.  The  disc  is  of  heavy 
brass  finely  finished,  provided  with  an  insulating  handle.  It  is  handsomely  finished  through¬ 
out  and  built  on  a  large  plan  so  that  it  may  be  used  to  advantage  on  the  lecture  table  .....  $9.25 

82-115  CAST-BASE  ELECTROPHORUS.  In  this  instrument,  above  illustrated,  we  secure  a  fine-quality 
instrument  capable  of  striking  results.  The  plate  consists  of  a  shallow  trough  casting  in  which 
is  moulded  a  cake  of  resinous  material.  The  disc  is  of  heavy  brass,  provided  with  an  insulating 
handle.  The  cast  metal  base  insures  insulating  material  against  breaking .  2.96 


GEAR  DRIVEN  INFLUENCE  MACHINES 

TOEPLER-HOLTZ  —  WIMSHURST 


The  demonstrator  will  be  gratified  to  receive  the  announcement  of  the  application  of  “gear  drive”  to  influence 
machines.  It  is  a  fact  generally  recognized  by  all  manufacturers  of  these  machines  that  the  simpler  the  machine, 
the  better  it  is  electrically,  providing,  of  course,  that  the  mechanism  will  hold  the  various  parts  in  their  proper  po¬ 
sitions  during  operation. 

The  greatest  drawback  to  obtaining  this  result  has  been  the  “belt  drive”  with  its  recognized  defects  in  slip¬ 
ping,  breaking,  slipping  off  the  pulley,  etc.,  etc.,  but  which  has  been  universally  used  because  of  its  low  cost  of  man¬ 
ufacture.  In  correcting  this  defect  and  to  enable  us  to  improve  our  product,  as  well  as  increase  the  efficiency  elec¬ 
trically,  we  have  selected  the  self-contained  gear  drive  in  which  accurately  cut  gears  operate  in  a  case  filled  with 
heavy  oil,  —  a  form  of  construction  which  automobile  manufacturers  have  brought  to  a  high  state  of  perfection. 
With  this  mechanism  the  power  is  applied  at  the  same  rigid  support  which  holds  the  main  axis  of  the  machine.  There 
is,  therefore,  no  tendency  to  change  the  relation  of  the  brushes,  collectors  and  plates,  as  all  are  mounted  on  this 
same  central  shaft. 

We  announce  two  types  of  Gear  Drive  Influence  Machines  both  of  which  have  the  same  important  character¬ 
istics  which  will  not  be  found  on  any  other  Influence  Machine,  European  or  American. 

On  the  following  page  we  list  the  Toepler-Holtz  Machines,  on  the  second  page  following,  the  Wimshurst  Ma¬ 
chines. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


291 


FEATURES  — DETAILS  OF  CONSTRUCTION 

The  following  important  features  and  details  of  construction  will,  we  are  confident,  impress  on  the  prospec¬ 
tive  purchaser  the  characteristic  quality  of  Knott’s  Gear-Drive  Influence  Machines. 

1 .  GLASS  PLATES  of  a  selected  quality  of  toughened  glass,  chemically  treated  and  coated  with  a  special 

varnish  which  gives  to  the  plates  a  durable,  hard  and  smooth  surface. 

2.  COLLECTOR  COMBS  are  particularly  efficient  in  collecting  the  plate  charge  with  little  loss.  They 

are  unusually  long  and  sharp  and,  since  centrally  mounted,  it  is  impossible  for  them  to  scrape 
against  collector  buttons. 

3.  COLLECTING  BRUSHES  will  be  found  a  decided  innovation.  The  Brush  Holder  is  of  the  spring 

clamp  type,  giving  a  positive  contact  and  can  be  attached  in  an  instant.  Brushes  are  readily 
adjusted  in  these  holders. 

4.  POSITIVE  GEAR  DRIVE,  —  accurately  cut  gears  operate  in  heavy  oil  within  the  oil-tight  gear 

casing. 

5.  INSULATION,  CONDENSERS  and  other  details  of  construction  have  been  most  carefully  considered 

and  all  details  combine  to  enable  the  demonstrator  to  secure  a  machine  particularly  well  adapted 
to  the  most  exacting  requirements. 

We  wish  once  more  to  call  to  attention  the  unit  method  of  mounting,  by  which  all  of  the  essential  parts  of  the 
machine,  together  with  the  motive  power,  are  attached  directly  to  the  rigidly  constructed  central  support. 


KNOTT’S  GEAR  DRIVE  TOEPLER-HOLTZ  MACHINES 


No.  82-160 


82-160  KNOTT’S  GEAR  DRIVE  TOEPLER-HOLTZ  MACHINE,  12  and  14-inch  plates,  gear  movement 
in  oil  tight  gear  case,  no  belts  to  loosen  or  get  out  of  order,  brushes  attached  by  spring  contacts, 
repair  bills  reduced  to  a  minimum.  Spark  one-third  diameter  of  plate . $19.00 

82-160  MULTIPLE  PLATE  GEAR  DRIVE  TOEPLER-HOLTZ  MACHINE,  four  plates  12  and  14  inches, 
gear  driven.  This  machine  has  all  the  improvements  detailed  above. 

The  value  of  the  multiple  plate  machine  has  long  been  recognized  by  the  manufacturers  of  X-Ray 
apparatus,  but  the  cost  of  construction  has  been  such  as  to  prohibit  the  general  use  in  educational 
work.  Our  method  of  standardizing  construction  enables  us  to  furnish  this  multiple  plate  ma¬ 
chine  at  a  cost  within  the  range  of  laboratory  work . 32.60 


292 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


KNOTT’S  WIMSHURST  GEAR  DRIVEN 
INFLUENCE  MACHINES 


This  type  of  machine  is  especially  recommended  for  localities  where  the  humidity  is  frequently  high,  as  it  is 
much  less  affected  by  atmospheric  conditions  than  any  other  type.  The  drive  mechanism  is  substantially  that  of 
the  Toepler-Holtz  Machines  described  on  the  previous  pages,  except  that  the  case  is  provided  with  another  set  of 
gears  in  order  to  give  the  revolution  in  two  directions.  The  advantages  of  the  gear  drive  in  this  type  of  machine 
are  particularly  noticeable  since  it  does  away  entirely  with  the  cross-belt  and  insures  that  both  plates  operate  at  the 
same  speed,  but  in  opposite  directions.  With  the  crossing  and  necessary  slipping  of  belts,  the  belt  drive  cannot  ac¬ 
complish  this  result. 


Our  improved  Gear  Drive  Wimshurst  Machines,  in  addition  to  the  most  important  manner  of  drive,  has  all 
mechanical  features  peculiar  to  our  Influence  Machines  as  described  on  page  291.  Applied  to  the  Wimshurst  Machine, 
these  features  enable  us  to  offer  a  machine  considerably  more  efficient,  of  greater  durability  and  more  easily  operated 
than  has  heretofore  been  offered. 


82-215  KNOTT’S  FOURTEEN-INCH  TWO-PLATE  GEAR-DRIVE  WIMSHURST  INFLUENCE  MA¬ 
CHINE,  glass  plates  chemically  treated  and  varnished,  mounted  according  to  latest  structural 
modifications  and  with  gear  drive,  insuring  a  uniform  speed  of  both  plates  in  opposite  directions. 

Spark  length  approximately  5  inches . $20.00 


BELT-DRIVE  RUBBER-PLATE  WIMSHURST  INFLUENCE  MACHINE 


No.  82-230 


82-230  EIGHT-INCH  TWO-PLATE  BELT-DRIVE  WIMSHURST  INFLUENCE  MACHINE.  The 

low  price  at  which  this  machine  is  offered  prohibits  the  use  of  our  enclosed  gear  drive.  The  belt 
drive  will  be  found  entirely  satisfactory  on  a  machine  of  this  size.  Spark  length  approximately 
3  inches .  . $10.00 


S  8  S  S 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


293 


STATIC  ELECTROMETERS 


83-10  PITH  BALLS,  assorted  plain  and  colored . Per  Dozen  $0.25 

—12  PITH  BALL  STATIC  ELECTROMETER,  attached  to  silk  cord,  ready  for  use  .  .  Each  .08 

-15  METALLIC  COATED  PITH  BALL,  vastly  more  sensitive  than  the  uncoated  . Each  .10 

-17  PITH  BALL,  one-inch  diameter . Each  .60 

-33  GOLD-LEAF,  PURE  GOLD,  in  book  form  for  electroscope . Per  Book  .76 

83-36  ALUMINUM-LEAF,  in  neat,  compact  roll,  especially  prepared  for  electroscope  work  .  Per  Roll  .36 

83-40  TIN  FOIL  for  Leyden  Jar  coatings,  Condensers,  etc . Per  Pound  1.26 


w 


No.  83-50 


83-50  GILDER’S  KNIFE,  PAD,  AND  TIP  for  cutting  gold-leaf. 

Frequent  statements  have  been  made  us  that  it  is  almost  impossible  to  replace  broken  leaf  on  electro¬ 
scopes.  This  trouble  arises,  principally,  from  lack  of  proper  tools.  The  outfit  illustrated  above 
will  facilitate  in  the  cutting  and  handling  of  even  the  finest  gold-leaf. 

Knife,  Pad,  and  Tip,  complete . $2.60 

83-76  PITH  BALL  ELECTROSCOPE  for  qualitative  demonstra¬ 
tion  of  static  charges. 

This  apparatus  consists  of  a  base  on  which  is  mounted  an 
insulated  support  with  arm.  To  this  arm  are  suspended 
two  pith  balls,  by  fine  silk  fiber . $0.55 

83-100  PITH  BALL  ELECTROSCOPE,  large  size  for  lecture  table 
demonstration.  Two  pith  balls,  1  inch  diameter,  mounted 
as  illustrated  in  No.  83-75  .  2.26 

83-106  CHRISTIAN  BROTHERS’  ELECTROSCOPE.  This  simple 
instrument  is  in  many  respects  superior  to  the  ordinary 
electroscope.  It  is  extremely  sensitive  and  acts  with  readi¬ 
ness  without  the  aid  of  drying  agents.  If  desired,  one  part 
of  it  may  be  charged  negatively  and  another  positively,  at 
the  same  time,  and  indications  are  readily  observed  by  all 
members  of  the  class. 

It  consists  of  an  insulating  stand  on  which  is  pivoted  an  ebonite 
needle  of  most  approved  size  and  shape  for  sensitive  work. 

The  only  directions  for  care  is  that  the  needle  should  be 
dismounted  when  not  in  use  and  wrapped  in  brown  paper 
so  as  to  exclude  light.  By  this  means  the  needle  is  always 
in  good  condition,  ready  for  instant  use . 80 


No.  83-75 


No.  83-106 


No.  83-110 


83-110  HARCOURT  ELECTROSCOPE  for  demonstrating  static  charges,  also  illustrating  an  electric  shield. 

This  apparatus  consists  of  a  metal  plate  in  the  center  of  which  is  placed  a  light  mounted  indicating 
needle.  A  metal  screen  with  insulating  handle  is  provided  for  placing  over  the  plate.  A  second 
mounted  needle  is  provided  on  top  of  the  metal  screen. 

Upon  the  approach  of  a  spark  from  a  Static  Machine  or  of  any  static  charge  it  may  be  demonstrated 

that  the  upper  needle  is  attracted  or  repelled  while  the  lower  remains  unaffected  . $1.76 


2Q4 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


83-136  STUDENT'S  ELECTROSCOPE,  simple  flask  form . . . $  0.60 

83-142  CAST  DRUM  GOLD-LEAF  PROJECTION  ELECTROSCOPE  for  use  as  an  electrometer  for 
general  laboratory  work,  but  especially  adapted  for  use  with  a  projection  lantern.  The  glass 
front  and  back  are  mounted  dust-proof,  but  may  be  readily  removed.  The  brass  rod  carrying 
the  gold-leaf  strips  is  insulated  with  pure  amber  set  in  vulcanite.  The  spun  metal  cup  (shown 
by  dotted  lines)  which  fits  loosely  over  a  collar  on  top  of  the  drum,  obstructs  radioactive  influences. 

The  general  design  and  structure  of  this  instrument  are  such  that  one  is  enabled  to  keep  a  charge  for 
long  periods  of  time.  Under  a  ten  days’  test  only  a  slight  loss  of  initial  charge  was  noted. 

The  ball  top  may  be  removed  when  it  is  desired  to  use  the  condenser  plate  attachment  for  demon¬ 
strating  that  the  plates  of  a  galvanic  cell  are  statically  charged. 

Electroscope,  complete  with  Plates  and  spun  metal  Protecting  Cup .  6.26 

83-143  CAST  DRUM  GOLD-LEAF  PROJECTION  ELECTROSCOPE,  without  Condenser  Plate  At¬ 
tachment,  but  with  Protecting  Cup .  4.00 

83-144  CONDENSER  PLATE  ATTACHMENT  for  use  with  No.  83-143  above,  in  demonstrating  that  the 
plates  of  a  galvanic  cell  are  statically  charged.  This  attachment  consists  of  two  plates  of  polished 
brass,  the  lower  in  illustration  to  replace  the  metal  ball,  the  upper  with  insulating  handle.  Plates 
with  special  dielectric .  2.25 

83-147  FECHNER’S  ELECTROMETER,  similar  to  above,  but  with  the  metal  leaves  adjusted  between  two 

highly  polished  metal  plates.  Complete  with  constant  voltage  Charging  Box . 11.60 

83-148  - ,  without  Charging  Box  . .  9.00 

83-160  BENNETT’S  GOLD  LEAF  ELECTROSCOPE  WITH  VOLTA’S  CONDENSING  PLATE  AND 
SAUSSURE’S  POINT  DISCHARGE.  This  instrument  is  intended  for  sensitive  work  in  testing 
electrification  of  a  body  and  in  determining  the  polarity  of  the  same.  In  our  design  we  use  the 
best  quality  of  electrical  glass  and  further  increase  the  conducting  quality  of  this  glass  by  ground¬ 
ing  it.  The  jar  used  is  of  special  mould  which  allows  of  the  use  of  the  various  attachments  without 
disturbing  the  gold  leaves.  As  a  Simple  Gold  Leaf  Electroscope  the  knob  top  alone  is  used.  When 
it  is  desired  to  use  the  Volta’s  Condensing  Plates,  this  knob  is  unscrewed  and  the  bottom  plate 
put  in  its  place.  Differing  from  the  usual  method  of  securing  a  condensing  surface  on  these  plates, 
we  furnish  with  each  instrument  a  special  dielectric  which  greatly  increases  the  condensing  power. 

The  bottom  plate  is  replaced  by  the  Saussure  Point  Discharge  when  it  is  desired  to  test  the  effects 
of  points  in  discharging  electricity  from  the  surface  of  a  conductor. 

This  electroscope  is  of  heavy  construction  and  is  handsomely  finished  throughout.  It  is  furnished 
complete  with  interchangeable  knob,  Volta’s  Condenser  Plates,  one  with  insulating  handle,  and 
with  Saussure’s  Point  Discharge .  8.76 


S'; 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


295 


THE  WILSON  RADIO-ELECTROSCOPE 

DESIGNED  FOR  RESEARCH  WORK  IN  RADIO-ACTIVITY 


83-165  THE  WILSON  RADIO-ELECTROSCOPE. 

This  instrument,  which  was  originally 
manufactured  at  the  request  of  the  De¬ 
partment  of  Physics  of  the  University  of 
Toronto,  instantly  met  with  much  favor 
among  all  workers  in  the  radio-active  field 
and  has  for  several  years  been  considered 
standard  for  high-grade  work. 

As  the  illustration  shows,  the  instrument  is 
especially  designed  for  telescope  reading,  a 
special  telescope  with  cross-hair  mounting 
having  been  designed  for  the  exact  measure¬ 
ment  of  the  angular  movement  of  the  gold 
leaf.  The  form  is  such  that  it  also  lends 
itself  perfectly  to  lantern  projection. 

INSULATION.  The  insulation  is  as  perfect 
as  the  purest  amber  can  make  it,  it  having 
remained  charged  for  48  hours  with  no  fall 
capable  of  being  detected  with  telescope 
reading. 

SELF  LEVELING.  Owing  to  the  method  of 
supporting  the  gold  leaf  member,  no  care  is 
required  in  leveling,  the  gimbal  bearing 
making  it  perfectly  automatic. 


No.  83-165 


METHOD  OF  USING  THE  RADIO-ACTIVE  MATERIAL.  The  opening  in  the  base  pillar,  seen 
in  the  illustration,  is  designed  for  the  ready  inserting  of  the  material  to  be  tested.  In  use, 
this  material  is  placed  in  a  small  watch  glass  and  inserted  in  the  opening,  the  outside  collar  then 
being  moved  up  to  exclude  all  air  currents  and  to  keep  the  conditions  within  the  instrument  as 
nearly  uniform  as  possible.  The  distance  between  the  radio-active  material  and  the  gold  leaf 
is  variable  and  easily  determined  by  the  number  of  discs  seen  in  the  illustration,  which  are 
placed  under  the  watch  glass,  thus  fixing  definitely  the  distance  between  the  radio-active  material 
and  the  gold  leaf.  It  will  thus  be  seen  that  all  conditions  have  been  carefully  considered  and 
provided  for. 

Price,  complete . $13.60 


83-170 


No.  83-170 


MOUNTED  TELESCOPE  FOR  RADIO-ACTIVE  WORK.  This 
telescope  has  been  designed  for  rapid  and  exact  measurement 
of  the  angular  drop  of  the  gold  leaf  due  to  the  gradual  loss  of 
potential  under  the  influence  of  the  radio-active  material.  A 
four-inch  graduated  dial  is  mounted  on  the  eye-piece  of  a  read¬ 
ing  telescope  in  such  a  manner  that  the  dial,  eye-piece  and 
cross-hair  move  as  a  rigid  unit.  The  angular  movement  of 
the  cross-hair  is  therefore  easily  read  by  the  dial  and  pointer. 

In  use,  the  eye-piece  is  rotated  until  the  cross-hair  is  parallel  to 
the  deflected  gold  leaf.  Note  the  reading  on  the  dial  in  degrees. 
After  the  lapse  of  a  single  unit  of  time,  the  dial  is  to  be  turned 
again  until  the  cross-hair  is  again  parallel  to  the  gold  leaf. 
The  difference  in  readings  on  the  scale  denotes  the  angular 
fall. 

Price  for  telescope  with  mountings  complete,  as  illustrated,  for 
radio-active  work . . . 

RADIO-ACTIVE  ELEMENTS.  See  No.  83-276 


16.26 


2g6 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


83-220  THE  RAYBOURN  QUADRANT  ELECTROMETER,  de¬ 
signed  to  meet  the  requirements  of  a  universal  instrument. 

By  means  of  the  telescoping  suspension  tube  we  are  able  to 
use  any  desired  length  and  type  of  suspension  so  as  to  ad¬ 
just  the  sensibility  of  the  instrument,  within  limits,  to 
any  desired  sensibility. 

As  carried  in  stock  it  is  supplied  with  a  50-centimeter  phos¬ 
phor  bronze  suspension  ribbon  which,  while  it  is  extremely 
durable,  will  give  ample  sensibility  for  most  purposes. 


DISTINCTIVE  FEATURES. 

1.  A  quadrant  box  of  open  construction  affording  easy  ac¬ 
cess  and  view  of  the  needle. 

2.  A  needle  of  very  light  weight,  aluminum  welded  to  the 
axis  wire  of  copper,  the  upper  end  of  which  is  bent  to 
form  a  hook  for  attaching  suspensions.  This  construc¬ 
tion  greatly  lessens  the  surface  resistance  of  the  metal, 
which,  in  case  of  an  aluminum  hook  ordinarily  used,  is 
very  great. 


No.  83-220 


3.  A  space  beneath  the  quadrants  is  ample  for  placing 
drying  material. 


4.  A  very  light  weight  optically  plane  mirror. 

5.  Pure  amber  insulation  throughout. 

6.  A  zero  adjustment,  simple  but  most  effective  and  impossible  of  accidental  derangement. 

7.  A  removable  metal  protecting  case  with  large  rectangular  opening  covered  by  a  window  of 
uniformly  thin  flat  glass. 

8.  Mounted  on  tripod  and  held  to  same  by  a  friction  clamp  which  permits  of  a  rotary  movement 
of  the  electrometer. 

9.  Binding  posts  and  links  permit  grounding  of  case  or  either  pair  of  quadrants. 

10.  Suspensions  may  be  readily  attached. 

11.  A  telescoping  support  allows  suspensions  of  any  desired  lengths  within  range  of  from  30  to  50 
centimeters. 

12.  Inasmuch  as  degree  of  sensibility  required  depends  upon  the  nature  of  the  work,  we  supply  our 
stock  instruments  with  a  metallic  suspension  50  centimeters  long.  These  suspensions  will  be 
found  very  durable  and  sufficiently  sensitive  for  all  work  except  where  extreme  sensibility  is 
required,  in  which  case  we  are  prepared  to  furnish  other  types  of  suspensions. 


We  confidently  recommend  this  instrument  for  all  classes  of  work  where  an  electrometer  of  superior 
sensitiveness  and  quality  is  required . 


83-222  CONSTANT  VOLTAGE  CHARGING  BOX,  —  designed  for  the  easy  and  convenient  charging  of 
Electroscopes  and  Electrometers,  maintaining  a  constant  difference  of  electrical  potential  of 
250  volts . 


$39.50 


2.50 


- , - 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


297 


ELECTROSCOPIC  ACCESSORIES 


No.  83-250 


83-260  WATER  BATTERY.  For  charging  the  needles  of  electrometers  and  for  gauging  electroscopes,  a 
battery  giving  real,  constant  and  well-defined  electromotive  forces  is  essential. 

It  has  50  cells,  mounted  on  substantial,  neatly  finished  wooden  base  and  is  particularly  adapted 
to  advanced  work  when  high  voltage  and  low  amperage  are  desired.  It  will  be  found  a  most 
serviceable  battery  for  all  electrostatic  electrometer  work . $6.25 

83-252  - ,  same  as  above,  but  comprising  100  cells.  This  battery  is  a  combination  of  two  of  the  above  12.76 


No.  84-10 


No.  84-15 


82-76  CHARGING  ROD  for  securing  either  positive  or  negative  charges  for  electroscopes.  For  descrip¬ 
tion,  see  page  289  . $6.50 

82- 77  THE  IMPROVED  POTENTIAL  BAR.  This  bar  is  designed  to  maintain  a  constant  potential  dif¬ 

ference  of  1000  volts,  mounted  in  form  for  convenient  and  satisfactory  use  with  Electroscopes, 
Electrometers,  Leyden  Jars  and  other  high  potential  electrical  instruments.  This  is  undoubtedly 
the  most  valuable  single  instrument  obtainable  for  the  study  of  electrostatic  phenomena  ....  9.60 

83- 275  RADIO-ACTIVE  SUBSTANCES.  For  the  convenience  of  those  who  desire  to  make  a  study  of  radio¬ 

activities  we  list  four  of  the  most  important  substances.  They  are  black  uranium  oxide,  pitch¬ 
blende,  thorium  nitrate  and  uranium  nitrate. 

Set  of  four  in  sealed  glass  stoppered  bottles .  3.60 

INSULATION  AND  CONDENSATION  OF  STATIC  ELECTRICITY 

84- 10  INSULATING  STOOL,  valuable  in  insuring  total  insulation  from  the  earth. 

This  stool  is  constructed  with  a  handsomely  finished  hardwood  top,  provided  with  four  glazed 

porcelain  legs  with  knob  feet,  the  insulating  qualities  of  which  are  unexcelled,  even  by  glass  .  .  .  2.50 

84-15  ADJUSTABLE  INSULATING  STAND,  solid  in  construction,  insulating  qualities  sufficient  for  all 
practical  purposes. 

Consists  of  a  supporting  plate  held  adjustably  by  two  vulcanite  rods  to  a  metal  base. 

Complete  as  illustrated .  2.60 


298 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  84-25  No.  84-30  Nos.  84-50  to  84-65 


84-20  PROOF-PLANE,  simple  disc  type  with  insulating  handle . $0.22 

84—25  GUARDED  DISCHARGER,  simple  form,  polished  brass  arc  with  ball  terminals  attached  to  a  polished 

ebonite  handle  with  disc  ebonite  guard .  1.26 

84-30  TWO-HANDLED  JOINTED  DISCHARGER,  two  highly  polished  brass  arcs  with  knob  terminals, 

jointed  to  provide  an  adjustable  gap,  each  arc  with  insulating  handle  of  ebonite .  2.76 

84-224  DISCHARGER,  lighter  construction  than  above,  ordinary  grade .  .66 

84—40  SHOCKING  HANDLES  AND  CORDS,  the  standard  form  used  in  testing  physiological  effects  of 
electrical  discharges.  Two  nickel-plated  metallic  handles,  one  with  insulated  carrier;  two  conducting 
cords,  each  cord  with  connector  tips.  Per  pair  with  cords .  1.00 


No.  84-60 


84-50  SIX-INCH  INDUCTION  AND  DISTRIBUTION  SPHERE 

for  showing  that  -a  charge  remains  on  the  outer  surface 
and  does  not  penetrate  into  the  interior. 

This  sphere  is  made  of  spun  brass,  highly  polished,  having 
a  hole  in  the  top.  It  is  mounted  on  a  neat,  brightly 


japanned  base  with  an  insulating  ebonite  pillar.  Diam¬ 
eter  6  inches .  6.00 

84-55  FOUR  AND  ONE-HALF  INCH  INDUCTION  AND 
DISTRIBUTION  SPHERE,  same  as  above  but  4J£ 
inches  in  diameter .  2.75 


84-67  INDUCTION  SPHERES,  brass,  nickel-plated,  5  cen¬ 
timeters  diameter.  Mounted  on  insulating  supports 
so  that  they  can  be  brought  in  contact  .  .Per  pair  3.30 

84-60  SIXTEEN-INCH  INDUCTION  CYLINDER  for  illus¬ 
trating  electrostatic  induction. 

This  apparatus  consists  of  a  polished  brass  cylinder,  16 
inches  in  length,  mounted  on  an  insulated  support  with 
tripod  base.  This  cylinder  is  provided  with  movable 
brass  supporting  arms  to  which  are  attached  pith  balls. 

If  a  positively  charged  sphere  be  brought  near  one  end  of 
the  cylinder,  that  end  will  become  negatively  charged 


while  the  opposite  end  will  be  positive .  7.80 

84-66  EIGHT-INCH  INDUCTION  CYLINDER,  similar  to 

above,  but  8  inches  long .  3.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


299 


No.  84-70 


84-70  HOLLOW  INDUCTION  CYLINDER  for  demonstrating  that  a 
charge  collects  on  the  surface  only. 

This  apparatus  consists  of  a  polished  brass  tube  supported  on  an 
ebonite  stem  attached  to  a  base.  It  is  provided  with  a  support 
for  pith  balls,  both  within  and  without  the  cylinder.  When 
charged,  pith  balls  without  the  cylinder  will  fly  apart,  while 
those  within  will  remain  unmoved,  demonstrating  that  the 
outside  only  is  charged . $1.95 

84-75  FARADAY’S  METAL  SHIELD  or  ELECTRIC  SCREEN  for 

covering  electroscopes,  illustrating  the  Marconi  system  of 
selecting  electric  signal  waves;  also  illustrating  the  principle 
of  protection  from  lightning. 

Mount  an  electroscope  on  a  metal  plate  placed  on  a  stand  or 
on  the  table  top.  Place  Screen  over  electroscope.  Allow  sparks 
from  a  Static  Machine  to  reach  the  Screen  and  note  leaves  of 
electroscope.  Remove  screen  and  metal  plate  and  test  leaves 
by  merely  approaching  a  charge  to  the  electroscope. 

Metal  Shield  only .  .46 


1%S!!SSKS&| 

nmsB 
I  isawsg 
tos^ejt 

BlJSI  i  li’S . ■ 

BSSSSl 


No.  84-75 


No.  84-80 


No.  84-86 


No.  84-90 


84-80  ELLIPSOIDAL  CONDUCTOR  for  demonstrating  the  tendency  of  static  distribution. 

This  design  consists  of  a  polished  brass  ellipsoidal  body  mounted  on  an  insulated  stem  with  a  neatly 

finished  base.  Size  of  ellipsoid,  inches  long,  inches  in  diameter . $4.50 


84-85  BIOT’S  HEMISPHERES  for  demonstrating  that  a  static  charge  seeks  the  outer  surface  of  a  body. 

This  apparatus  consists  of  two  polished  brass  hemispheres  with  insulating  handles.  These  hemi¬ 
spheres  are  designed  to  fit  over  No.  84-55  Induction  and  Distribution  Sphere. 

When  the  globe  is  electrified  and  two  hemispheres  are  placed  over  it,  and  then  removed,  it  will  be 
found  that  they  have  become  electrified  while  the  globe  has  lost  its  charge. 

Biot’s  Hemispheres,  only .  2.25 


84-86  BIOT’S  HEMISPHERES  and  NO.  84-65  INDUCTION  AND  DISTRIBUTION  SPHERE,  com¬ 
plete  as  illustrated .  6.00 

84-90  RITCHIE’S  SURFACE  AND  INTENSITY  APPARATUS  for  showing  the  variation  of  electrical  den¬ 
sity  on  a  unit  of  surface  as  that  surface  is  diminished  or  increased. 

This  ingenious  instructive  instrument  consists  of  a  special  clamp  in  which  fits  the  roller  insulated  from 
the  clamp.  Around  this  roller  is  wound  tin  foil.  An  electrometer  in  metallic  contact  with  the  tin 
foil  indicates  the  quantity  of  electrical  force. 

When  the  tin  foil  is  rolled  up,  a  charge  is  imparted  to  it  by  which  a  certain  divergence  is  produced 
on  the  balls  of  the  electrometer.  On  unrolling  the  tin  foil  this  divergence  gradually  diminishes  but 
increases  as  it  is  rolled  up  again. 

The  clamp  of  this  instrument  may  be  attached  to  any  19-millimeter  rod. 

Without  supporting  stand .  3.80 


300 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  84-100 


84-100  FARADAY’S  CONICAL  NET.  A  net  1 1  inches  long  by  5  inches  diameter  on  insulating  mount  for 
demonstrating  that  a  static  charge  will  always  reside  on  the  outside.  The  apparatus  consists  of  a 
conical  bag  of  linen  gauze,  supported  on  an  insulating  stand  and  to  which  are  attached  silk  strings 
by  which  it  may  be  turned  inside  out. 

In  use,  this  conical  bag  is  charged,  which,  by  tests,  may  be  shown  to  reside  on  the  outside  only. 

When  pulled  inside  out,  and  tested,  it  will  be  found  that  the  charge  still  is  on  the  outside,  having 

passed  through  the  gauze . $1.65 

84-125  BELL  CHIMES,  illustrating  electrostatic  attraction  and  repulsion  between  electrified  bodies. 

This  apparatus  consists  of  an  insulated  stand  to  the  top  of  which  are  attached  three  cross-heads,  to 
the  ends  of  each  of  which  are  attached  bells  suspended  by  brass  chains.  The  lengths  of  these 
chains  are  adjusted  so  that  all  six  will  be  in  the  same  plane  as  a  large  bell  mounted  to  the  insulat¬ 
ing  support.  Also  mounted  to  these  cross-heads  are  six  silk  cords  each  holding  a  small  metal  ball. 

The  lengths  of  these  cords  are  adjusted  so  that  the  balls  will  lie  in  the  same  plane  as  the  bells. 

When  this  apparatus  is  electrified,  the  small  balls  will  be  attracted  and  repelled  between  the  large 

bell  and  the  small  bells,  causing  a  continuous  jingle .  9.00 

84-130  UNMOUNTED  BELL  CHIMES,  ordinary  type . 90 


84-165  IMAGE  PLATES  for  illustrating  the  phenomenon  of  attraction  and 
repulsion. 

This  apparatus  consists  of  two  nickel-plated  discs  suspended  one  to  the 
other  by  insulating  cords.  To  the  upper  disc  is  fastened  a  nickel- 
plated  hook  for  attaching  to  the  Static  Machine;  the  lower  is  provided 
with  a  chain  for  securing  connection  with  the  ground  or  opposite  pole  of 
Static  Machine. 

In  use  the  pith  images  are  placed  between  the  two  plates.  They  will  dance 
up  and  down  as  they  become  charged  with  positive  and  negative 
electricity .  1.80 

84-157  PITH  IMAGES,  a  pair  of  images  constructed  of  pith  for  use  with  No. 

84-155  Image  Plates . Per  Pair  .40 

84-176  POLE-TEST  PAPER.  When  two  electrical  leads  are  placed  close  to¬ 
gether  upon  a  moistened  strip  of  this  paper,  the  negative  pole  may  be 
distinguished  by  the  pinkish  stain  which  it  leaves  .  .  Per  Sheet  .05 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


301 


ELECTROSTATIC  PHENOMENA 


The  following  accessories  will  be  found  interesting  for  lecture  work.  With  even  the  smallest  size  Influence 
Machine,  a  great  variety  of  interesting  experiments  may  be  performed.  The  workmanship  of  each  accessory  is  ac¬ 
curate  and  under  proper  conditions  the  desired  phenomena  may  be  strikingly  illustrated. 

As  each  accessory  is  designed  to  fit  our  No.  84-200  Universal  Stand,  only  one  stand  will  be  found  necessary. 


84-200  UNIVERSAL  STAND.  May  be  used  with  all  accessories  listed .  $  1.00 

84-202  PAPER  BRUSH.  When  discharged,  paper  strips  will  stand  out  as  illustrated  .  .65 

84-204  BELL  CHIMES,  consisting  of  five  harmonically  tuned  bells  which,  when  connected  to  Influence 

Machine,  will  cause  small  balls  to  rapidly  vibrate  back  and  forth  between  them .  2.60 

84-206  DANCING  BALLS  AND  HOLDER.  Apparatus  connected,  the  balls  will  dance  within  the  holder  2.70 
84-208  WHIRL.  When  connected  to  Influence  Machine,  charge  will  leap  rapidly  from  points,  causing  a 

rotary  motion  .  .70 

84-210  HOLDER  FOR  GEISSLER  TUBE  AND  LIGHT¬ 
NING  PLATE . 60 

84-212  EBONITE  LIGHTNING  PLATE.  Spectacular 

sparks  across  gaps  in  tin  foil  when  connected 

with  Influence  Machine .  1.20 

84-214  LIGHTNING  SPIRAL  TUBE.  Spectacular  spiral 
of  sparks  across  gaps  in  tin  foil  when  connected 

with  Influence  Machine .  1.60 

84-216  BALL  RACE.  Hollow  glass  sphere  will  race  rapidly 

around  track  when  connected  to  Influence  Machine  1.66 
84-218  SMOKE  CONDENSATION  APPARATUS.  The 

smoke  from  a  smoke  handle  within  a  glass  holder 
is  condensed  when  connected  to  an  Influence  Ma¬ 
chine,  entirely  disappearing .  2.70 

84-220  SHOCKING  HANDLES  for  electrifying  persons  .60 

84-222  LEYDEN  JAR,  best  glass,  heavy  tin  foil  covering, 

4  inches  high .  1.10 

84-224  DISCHARGER  . 66 

84-226  CONDUCTOR  CHAINS  for  connecting  accessories 

to  Influence  Machine .  .26 

84-230  DEMONSTRATION  SET  for  illustrating  electro- 
statical  phenomena.  For  the  convenience  of 
those  who  desire  to  order  a  complete  set,  we 
furnish  the  set  as  listed  above,  Nos.  84-200  to 
84-226,  enclosed  in  a  strongly  constructed  card¬ 
board  box  divided  into  compartments . 16.50 


302 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


SUPPLEMENTARY  DESIGNS 

ELECTROSTATIC  PHENOMENA 


No.  84-240 


No.  84-244 


No.  84-250 


No.  84-242 


No.  84-248 


No.  84-246 


No.  84-252 


No.  84-254 


No.  84-256 


No.  84-268 


No.  84r-260 


ELECTROSTATIC  MOTOR;  the  ebonite  spider  with  the  metallic  balls  is  rotated  rapidly  when 

connected  to  an  Influence  Machine . . . $5.25 

GLASS  PENETRATING  APPARATUS  for  producing  breath  pictures  and  for  penetrating  glass. 

When  connected  to  an  Influence  Machine,  the  imprint  of  a  coin  will  be  invisible  until  the  glass  is 
breathed  upon.  With  this  apparatus,  also,  a  glass  plate  Y%  inch  in  thickness  will  be  penetrated  by 

a  spark  even  from  the  smallest  Influence  Machine .  3.16 

SAND  APPARATUS.  Fine  glass  sand  placed  in  the  funnel  will  emerge  through  the  hole  in  the 
bottom  in  the  form  of  a  straight  stream.  When  funnel  is  electrified,  the  sand  grains  will  repel 
each  other,  causing  the  stream  to  spread  out  and  the  fine  grains  will  fall  with  a  spattering  noise  .  1.96 

QUADRANT  ELECTROMETER.  When  not  charged,  the  ball  will  lie  against  the  metallic  rod. 

When  charged,  the  ball  will  be  repelled  and  according  to  the  strength  of  the  machine  to  which  it  is 

connected,  will  show  a  large  or  small  deflection . . .  2.35 

ELECTRIC  MORTAR.  When  connected  with  an  Influence  Machine,  a  spark  will  jump  across  the 
inside  of  the  mortar.  The  air  is  suddenly  expanded  and  the  ball  lying  loose  on  the  top  is  thrown 
up  into  the  air.  If  a  Leyden  Jar  is  also  connected,  there  will  be  an  explosion  and  the  ball  will  fly 

a  considerable  distance . . .  1.36 

BEETZ’  ELECTROSCOPE  for  demonstrating  that  a  charge  collects  on  the  surface  only.  When 
apparatus  is  electrified,  the  two  balls  at  the  top  will  fly  apart  while  those  within  the  cylinder  will 

show  no  movement . _ .  1-65 

CANDLE  EXPERIMENT  for  demonstrating  that  negative  electricity  will  repel  a  flame  and  that 
positive  will  attract.  This  apparatus  will  also  show  the  so-called  electric  wind,  which  may  be  so 
strong  that,  when  in  proper  position,  the  candle  is  extinguished.  An  extra  ball  with  a  point  is 
supplied  to  replace  one  of  the  balls  with  hook  on  the  ebonite  collar.  In  performing  this  experi¬ 
ment,  both  balls  with  hooks  must  be  removed  from  the  pillars .  1.95 

REVOLVING  DISC.  The  ebonite  disc  which  is 
studded  with  small  colored  circles  for  obtain¬ 
ing  a  better  visibility  is  made  to  revolve  rapid¬ 
ly  in  consequence  of  the  radiation  of  the 
electricity  from  the  points  beneath  it  .  .  .  $2.00 

RADIATION  APPARATUS.  After  the  appara¬ 
tus  has  been  connected  to  the  Influence  Ma¬ 
chine,  a  luminous  circle  will  be  seen  in  the 
dark  radiating  from  the  disc  to  the  ring  .  .  1.95 

LIGHTNING  CONDUCTOR.  A  small  quan¬ 
tity  of  benzine  or  ether  is  placed  in  the  small 
dish.  The  point  resembling  a  lightning  con¬ 
ductor  is  unscrewed  from  the  knob  mounted 
on  the  ebonite  pillar.  If  a  spark  is  now 
caused  to  strike  this  knob,  the  contents  of  the 
dish  will  be  ignited.  If  point  is  replaced  and 
grounded  by  a  chain  and  experiment  re¬ 
peated,  there  will  be  no  ignition  as  the  spark 
will  be  slowly  discharged  through  the  point  .  2.36 

84-260  IGNITION  APPARATUS.  By  means  of  a 
spark  from  a  Leyden  Jar,  small  pieces  of 
ignition  paper  are  ignited.  With  extra  supply 

of  ignition  paper .  1.76 

84-266  SUPPLEMENTARY  DEMONSTRATION  SET, 
consisting  of  Nos.  84-240  to  84-260  together 

in  a  strongly  constructed  wood-reinforced  „ _ _ _ _ _ .... 

cardboard  box,  divided  into  compartments  19.76  No.  84-266 


84-240 

84-242 

84-244 

84-246 

84-248 

84-260 

84-262 

84-254 

84-256 

84-258 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


303 


STORAGE  OF  STATIC 


No.  85-10  No.  86-15 


ELECTRICITY 

© 


No.  85-40 


86-10  DEMONSTRATION  LEYDEN  JAR  for  demonstrating  that  an  electric  charge  resides  as  potential 
energy  in  the  glass  of  a  Leyden  Jar  and  not  in  the  metallic  coatings. 

This  is  a  dissectible  Leyden  Jar,  the  outer  metallic  covering  being  removable  as  well  as  the  inner.  The 
inner  is  provided  with  a  rod  with  ball  terminal  for  charging.  This  form  must  not  be  confused  with 
the  many  types  on  the  market.  We  use  a  special  form  of  toughened  glass  for  our  glass  jar  and  our 
coatings  are  of  polished  brass.  The  instrument  presents  a  handsome  appearance  and  readily  recom¬ 


mends  itself  in  comparison  with  other  makes . $2.90 

85- 16  QUART  LEYDEN  JAR  for  storing  static  electricity. 

This  jar  is  constructed  of  a  special  quality  of  toughened  glass,  the  coatings  being  smoothly  applied. 

Provided  with  insulating  cover  through  which  passes  a  rod,  one  end  of  which  is  terminated  in 

a  knob.  To  the  other  is  attached  a  chain  making  connection  with  the  inner  coating .  1.60 

86- 20  TWO- QUART  LEYDEN  JAR,  same  quality  as  above .  2.00 

86-26  LEYDEN  JAR,  as  used  on  our  12-inch  Toepler-Holtz  Influence  Machines .  1.00 

86-30  LEYDEN  JAR,  as  used  on  our  16-inch  Toepler-Holtz  Influence  Machines .  1.10 

86-40  LUMINOUS  LEYDEN  JAR  for  demonstrating  optically  the  distribution  of  static  electricity  over 
the  surface  of  a  condenser  being  charged  and  discharged. 

This  jar  is  of  the  same  size  as  our  No.  85-20,  but  is  coated  inside  and  out  with  a  tin-foil  coating  which 
is  not  continuous  but  cut  diamond-shaped .  3.15 


LEYDEN  JAR  BATTERIES 

These  consist  of  a  series  of  Leyden  Jars  as  previously 
listed,  arranged  so  that  their  inner  coatings  are  connected 
to  one  terminal  and  their  outer  coatings  to  another,  thus 
securing  a  larger  area  of  coated  surface  than  is  contained 
in  one  jar.  With  an  arrangement,  therefore,  of  more  than 
one  jar  connected  in  this  manner  it  can  be  demonstrated 
that  the  capacity  of  a  condenser  is  directly  proportional  to 
the  area  of  its  coated  surface.  This  will  be  demonstrated 
by  the  greater  time  it  takes  to  charge  the  battery  and 
the  more  powerful  spark  obtained. 

In  the  form  of  battery  above  illustrated  we  furnish 
one  in  which  all  connections  are  open  to  view.  The  jars 
are  made  of  the  same  high  quality  of  di-electric  glass  as 
used  in  all  our  Leyden  Jars.  They  are  placed  in  a  box 
lined  with  heavy  tin  foil  which  serves  to  connect  the  outer 
coatings  with  the  jars.  The  inner  coatings  are  connected 
by  means  of  brass  chain. 

85- 60  TWO- JAR  LEYDEN  BATTERY  ....  $  6.80 

86- 66  FOUR-JAR  LEYDEN  BATTERY  .  .  .  11.70 

86-70  SIX- JAR  LEYDEN  BATTERY . 16.00 


No.  86-65 


304 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


86-100 


86-106 


86-110 


PLATE  CONDENSERS 


No.  86-100 


DISSECTEBLE  DEMONSTRATION  PLATE  CONDENSER  for  a  study  of  induction  in  a  condenser. 

This  apparatus  consists  of  a  neatly  finished  wooden  base  on  which  are  mounted  three  insulating  up¬ 
rights.  On  the  central  upright  is  mounted  a  glass  plate,  on  each  of  the  others  a  rod  sliding  in 
a  hole  at  the  top  of  the  upright.  Each  rod  carries  at  one  end  a  brass  plate,  at  the  other  an  in¬ 
sulating  handle.  All  parts  are  carefully  assembled  and  metal  work  polished  and  lacquered. 

By  means  of  a  suitable  electrometer  the  density  and  distribution  of  a  charge  under  various  conditions 

may  be  readily  determined . $9.60 

MOUNTED  CONDENSER  PLATES,  after  Millikan,  Gale  and  Bishop  (Experiment  27)  .  .  Pair  .26 


No.  86-110 


MOUNTED  GLASS  PLATE  CONDENSER  for  use  as  a  Leyden  Jar  Battery  in  accumulating  and 
storing  static  charges. 

This  condenser  consists  of  a  neatly  finished  hardwood  frame  in  which  are  mounted  five  condenser 
plates  constructed  of  the  best  quality  toughened  glass  and  having  a  total  condensing  surface  area 
of  1,620  square  centimeters.  Two  parallel  conductor  rods  mounted  at  the  top  of  the  frame  over  the 
plates  and  provided  with  contact  arms  for  connecting  any  number  of  plates  desired  up  to  five 
serve  to  charge  the  condenser. 

Complete  as  illustrated  . $14.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


305 


ELECTRICAL  DISCHARGE  TUBES 

GEISSLER  TUBES 

Our  collection  of  GEISSLER  TUBES  has  been  selected  with  the  greatest  care,  the  basis  of  selection  being  that 
of  the  greatest  color  effects  with  didactic  illustrative  features.  These  tubes  are  manufactured  by  one  of  the  most 
prominent  manufacturers  in  Europe  whose  name  is  a  sufficient  guarantee  of  quality.  Each  tube  is  provided  with 
strong  terminals  sealed  securely  in  a  manner  to  obviate  frequent  breakages  at  terminal  points. 

These  tubes  are  constructed  of  uranium  and  white  glass  formed  into  various  shapes  for  producing  pleasing  optical 
effects.  The  air  is  then  evacuated  and  the  tubes  are  sealed. 


86-10  GEISSLER  TUBES,  plain,  set  of  six  different  shapes,  6  inches  (15  centimeters)  long,  enclosed  in  neat 

cardboard  case  .  . $3.00 

86-11  - ,  same  as  above . Each  .60 

86-15  GEISSLER  TUBES,  similar  to  above,  but  more  complicated  in  form,  presenting  more  pleasing  effects, 

set  of  six,  12  inches  (30  centimeters)  long,  in  neat  cardboard  case .  6.70 

86-16  - ,  same  tubes  as  contained  in  above  set . Each  .95 


No.  86-25 


86-26 

86-26 

86-30 


FLUORESCENT  GEISSLER  TUBES.  These  tubes  are  constructed  in  a  manner  similar  to  above, 
but  filled  with  fluorescent  liquids  such  as  eosine,  quinine,  kerosene,  sesculine,  and  uranine. 

These  tubes  present  very  handsome  colors  and  are  highly  recommended.  Set  of  six,  6  inches  (15 

centimeters)  long,  enclosed  in  neat  cardboard  case . 

- ,  same  tubes  as  contained  in  above  set . Each 

FLUORESCENT  GEISSLER  TUBES,  similar  to  above,  but  more  complex  in  form.  Length  12  inches 
(30  centimeters).  Set  of  six  in  neat  cardboard  case 


,  same  tubes  as  contained  in  above  set 


$5.40 

.90 

9.90 

1.65 


86-31 


Each 


306 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


86-40 


86-46 


FOURTEEN-INCH  LECTURE  TABLE  GEISS¬ 
LER  TUBES.  These  tubes  are  designed  to 
illustrate  the  principal  types  of  Geissler  tubes. 

They  are  14  inches  (35  centimeters)  long  and 
give  remarkably  beautiful  results.  Set  of 
seven  tubes  as  follows:  ■ 

(1)  Double  Tube,  containing  two  fluores¬ 
cent  liquids. 

(2)  Double  Tube,  containing  two  phos- 

rhorescent  substances. 

Highly  Evacuated  Tube,  constructed 
of  uranium  and  white  glass. 

(4)  Double  Tube,  containing  two  gases. 

(5)  Mercury  Tube.  Will  show  phosphor¬ 
escence  by  shaking  mercury  in  the  tube. 

(6)  Tube  containing  a  mercury  salt  which 
changes  colors  as  heated. 

(7)  Tube  showing  layers  of  light. 

Set  complete,  in  neat  cardboard  case  ....  $14.80 

FLUORESCENT  GEISSLER  TUBE,  containing 
two  fluorescent  liquids,  illustrating  fluorescence 
of  different  colored  liquids . .  2.36 


No.  86-40 


86-46  PHOSPHORESCENT  GEISSLER  TUBE,  containing  two  phosphorescent  substances . $2.10 

86-47  GEISSLER  TUBE,  constructed  of  uranium  and  white  glass,  highly  evacuated,  to  illustrate  colors 

through  different  qualities  of  glass .  2.00 

86-48  GEISSLER  TUBE,  containing  two  different  gases .  2.00 

86—49  PHOSPHORESCENT  MERCURY  TUBE.  This  tube  does  not  require  use  of  Influence  Machine 
or  Induction  Coil,  as  phosphorescence  of  the  mercury  may  be  shown  by  simply  shaking  it  from  one 
end  of  the  tube  to  the  other .  2.60 

86-60  PHOSPHORESCENT  GEISSLER  TUBE,  containing  a  mercury  salt  which  exhibits  different  colors 

as  it  is  heated .  2.10 

86-61  GEISSLER  TUBE,  constructed  to  show  various  strata  of  light .  2.00 


No.  86-60 


No.  86-62 


No.  86-64 


No.  86-66 


86-60  GEISSLER  TUBE,  improved  form,  constructed  of  uranium  and  white  glass  and  filled  with  various 
fluorescent  liquids,  mounted  on  glass  foot,  and  provided  with  strengthened  terminals  for  connec¬ 
tion  to  Influence  Machine  or  Induction  Coil.  Height  6  inches .  $1.66 


86-62  GEISSLER  TUBE,  improved  form,  as  above,  but  of  different  shape  and  more  complicated  design. 

Height  6  inches  (15  centimeters) .  1.76 

86-64  GEISSLER  TUBE,  similar  to  above,  but  more  complicated  design,  height  6  inches  (15  centimeters)  1.96 

86-66  GEISSLER  TUBE.  The  design  illustrated  excels  in  colors.  It  is  designed  to  show  fluorescence  of 
three  different  colored  liquids  and  two  gases,  as  well  as  the  colors  of  uranium  and  white  glass.  It  is 
mounted  on  glass  foot  and  is  6  inches  (15  centimeters)  high . 


2.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


307 


No.  86-76 


86-75  UNEQUALLY  EVACUATED  GEISSLER  TUBES  for  showing  effects  upon  a  spark 
as  it  passes  through  tubes  filled  with  unequally  attenuated  air. 

This  apparatus  consists  of  five  connected  Geissler  Tubes,  each  of  which  has  a  dif¬ 
ferent  degree  of  exhaustion. 

In  the  least  exhausted  tube  the  spark  is  well  defined,  but  as  the  vacuum  increases, 
this  spark  begins  to  widen  out  and  fill  the  whole  tube,  becoming  pale  in  tint 
and  nebulous  in  form . Per  set  of  five  $8.90 

86-86  EXPERIMENTAL  BAROMETER  VACUUM  AND  GEISSLER  TUBE.  The  tube 
illustrated  is  designed  for  the  purpose  of  making  a  critical  study  of  the  vacuum 
in  a  barometer  tube,  Geissler  tube,  Crooke’s  tube  and  X-Ray  tube. 

Platinum  electrodes  are  inserted  in  both  the  upper  and  lower  end  of  the  tube.  The 
mercury  reservoir  holds  sufficient  mercury  to  fill  the  entire  chamber.  The 
length  of  the  tube  is  such  as  to  allow  ample  vacuum  space  above  the  mercury 
under  complete  exhaustion.  The  air  is  exhausted  through  the  tubulature  at 
the  top  of  the  tube,  while  the  reservoir  is  filled  through  the  tubulature  in  the 
base. 

For  the  study  of  the  barometer,  the  Cooper-Hewitt  Lamp,  the  Geissler  tube,  the 
Crooke’s  tube,  the  X-Ray  tube  and  all  electrical  phenomena  under  reduced  at¬ 
mospheric  pressure,  we  consider  this  the  most  important  piece  of  apparatus  that 
has  ever  been  offered .  3.25 


GEISSLER  TUBE  ROTATORS 


86-100 


86-102 

86-104 

86-110 


GEISSLER  TUBE  ROTATOR  for  rotating  Geissler  Tubes 
to  increase  the  spectacular  effect. 

Our  Rotator  consists  of  a  practical  motor  (not  a  toy)  con¬ 
structed  after  designs  of  the  expensive  commercial  types. 

It  is  mounted  upon  a  substantial  metal  pedestal  support 
and  is  provided  with  appropriate  binding  posts,  one  pair 
for  battery  or  other  current  and  one  pair  for  induction 
coil  or  Influence  Machine.  The  Geissler  tube  is  at¬ 
tached  to  the  holder,  which  may  be  firmly  fixed  to  the 
spindle  of  the  rotator.  This  holder  is  adjustable  to 
take  any  Geissler  tube  up  to  12  inches  in  length. 

Motor  only,  with  Geissler  tube  attachment,  motor  wound 

for  battery  current . $12.00 

- ,  same  as  above,  but  motor  wound  for  110  volts,  D.  C.  13.25 

- ,  same  as  above,  but  motor  wound  for  110  volts,  A.  C.  13.25 

GEISSLER  TUBE  HOLDER  for  use  with  our  No.  21-10 
Mechanical  Rotator  or  our  No.  21-30  Motor  Rotator, 
to  hold  Geissler  Tubes  for  rotation. 

This  holder  can  be  firmly  attached  to  the  spindle  of  either 
of  these  rotators  and  is  adjustable  to  hold  all  sizes  of 
Geissler  tubes  up  to  12  inches  long .  2.70 


No.  86-100 


3o8 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


SPECTRUM  AND  VACUUM  TUBES 


Nos.  77-225  to  77-236  No.  77-245 


77-225  GEISSLER  SPECTRUM  TUBE,  most  careful  construction,  filled  with  carbon  dioxide . $1.95 

77-226  - ,  filled  with  hydrogen  gas  .  1.95 

77-227  - ,  filled  with  nitrogen  gas . 1.96 

77-228  - ,  filled  with  oxygen  gas  . 1.95 

77-235  GEISSLER  SPECTRUM  TUBE,  most  carefully  constructed,  evacuated,  and  filled  with  pure  argon 

gas .  7.75 

77-236  ,  same  as  above,  but  filled  with  helium .  7.75 

77-245  GEISSLER  SPECTRUM  TUBE  for  evacuating  and  filling  with  whatever  gas  desired.  Fitted  with 

two  carefully  ground  glass  cocks .  1.96 


86-150  DE  LA  RIVES  APPARATUS  for  showing  that  magnets  act  on  light  in  Geissler 
tubes  in  accordance  with  the  laws  with  which  they  act  on  any  other  movable 
conductor. 

The  apparatus  consists  of  a  highly  evacuated  bulb  sealed  into  the  lower  end  of 
which,  and  extending  up  into  the  bulb,  is  a  tube,  into  which  extends  a  rod  of 
soft  iron.  This  rod,  in  use,  is  magnetized  by  an  electro-magnet. 

Terminals  of  the  bulb  are  connected  to  an  electrostatic  current  or  current  from 
an  induction  coil,  and  a  beam  of  light  passes  from  one  terminal  to  the  other. 

When  the  voltaic  current  is  turned  through  the  electro¬ 
magnet,  this  beam  of  light  turns  slowly  about  the  mag¬ 
netized  rod,  sometimes  in  one  direction,  sometimes  in 
the  other,  according  to  the  direction  of  the  induced  current 
or  of  the  induced  magnetism. 

Complete  with  electro-magnet . 


$5.90 


No.  86-150 


No.  86-160 


86-165 


No.  86-170 


86-160 


86-165 


VACUUM  TUBE  for  showing  the  heating  effect  of  the  cathode  ray.  The  negative  electrode  is  in 
the  form  of  a  mirror,  designed  to  focus  the  cathode  ray  upon  a  piece  of  platinum  foil,  heating  it 
white  hot  in  a  very  short  time . 


$7.75 


VACUUM  TUBE  for  showing  the  deflection  of  a  cathode  ray.  On  one  side  of  an  evacuated  tube  is 
a  fluorescent  screen  with  a  strip  with  slit  at  right  angles.  This  strip  absorbs  the  cathode  rays 
except  those  which  pass  through  the  slit.  By  holding  a  magnet  to  the  tube,  it  may  be  shown  that 
this  beam  is  deflected  as  indicated  by  its  path  on  the  fluorescent  screen .  6.60 


86-170  VACUUM  TUBE  for  showing  the  power  of  a  body  to  interpose  the  cathode  ray.  When  the  dis¬ 
charge  passes,  the  cathode  rays  proceed  in  straight  lines.  The  small  cross,  however,  interposes  a 
number  of  these  molecules  and  a  shadow  of  the  cross  is  cast  on  the  opposite  side  of  the  tube  .  .  . 


7.25 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


309 


ROENTGEN  RAY  APPARATUS 

X-RAY  TUBES 


Nos.  87-40  to  87-50 


The  following  four  tubes  are  for  use  with  small  enclosed  Static  Machines  and  Spark  Coils  operated  by  battery 
current  which  give  sparks  of  from  four  to  six  inches  in  length.  We  frequently  have  requests  for  X-Ray  tubes  to  be 
used  with  small  unenclosed  Static  Machines  and  small  Ruhmkorff  Coils,  but  none  of  these  tubes  will  give  satisfactory 
results  and  we  have  not  included  any  in  this  series. 

87-10  AUTOMATICALLY  ADJUSTED  X-RAY  TUBE,  4  inches  in  diameter  with  heavy  platinum  target 


and  with  special  attachment  for  maintaining  automatically  the  proper  degree  of  vacuum  ....  $9.80 

87-15  X-RAY  TUBE,  4  inches  in  diameter  with  heavy  platinum  anode  the  same  as  above,  but  without  the 

automatic  adjuster .  7.50 

87-20  AUTOMATICALLY  ADJUSTED  X-RAY  TUBE,  534  inches  in  diameter  with  heavy  platinum  anode 

and  with  automatic  adjuster . 12.25 

87-26  - ,  6  inches  in  diameter  with  heavy  platinum  anode  and  automatic  adjuster . 16.40 


The  following  three  tubes  are  for  use  with  large  enclosed  Static  Machines  and  with  large  Induction  Coils  operated 
by  power  current  with  Electrolytic  Interrupter. 

87-40  AUTOMATICALLY  ADJUSTED  X-RAY  TUBE,  6  inches  in  diameter  with  heavy  platinum  anode 

and  automatic  adjuster . $22.00 

87-45  - ,  7  inches  in  diameter  with  heavy  platinum  anode  and  automatic  adjuster . 27.75 

87-50  - ,  8  inches  in  diameter  with  heavy  platinum  anode  and  automatic  adjuster . 33.50 


The  following  two  tubes  are  for  use  with  Tesla  and  High  Frequency  Coils. 

87-60  AUTOMATICALLY  ADJUSTED  X-RAY  TUBE,  5J4  inches  in  diameter  with  especially  constructed 

platinum  anode  and  automatic  adjuster . 20.40 

87-65  - ,  6  inches  in  diameter  with  especially  constructed  platinum  anode  and  automatic  adjuster  .  .  22.60 

(We  recommend  the  use  of  the  above  two  tubes  with  our  High  Frequency  Coils,  Section  96.) 


The  following  three  tubes  are  recommended  for  the  very  heaviest  machines  and  the  most  exacting  work  that 
can  be  put  upon  the  X-Ray  tube.  The  anode  is  of  heavy  sheet  Tungsten  which  will  fuse  only  at  a  temperature  of 
3,000  Centigrade,  and  for  X-Ray  work*is  practically  indestructible.  These  three  tubes  are  the  latest  and  best  prod¬ 


uct  in  X-Ray  tube  construction. 

87-70  TUNGSTEN  X-RAY  TUBE,  latest  construction,  6  inches  in  diameter . $38.00 

87-75  - ,  same  as  above,  7  inches  in  diameter . 44.60 

87-80  - ,  8  inches  in  diameter . 49.26 


3io 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


87-100  SMALL  X-RAY  STAND,  universal  adjustment . $2.50 

87-110  LARGE  X-RAY  STAND,  with  heavy  iron  base.  This  stand  is  four  feet  tall  and  is  arranged  for 

adjustment  in  all  directions . 11.00 


Nos.  87-126  to  87-146 


Nos.  87-126  to  87-146 

87-126  BARIUM  PLATINO-CYANIDE  FLUOROSCOPE  AND  SCREEN,  3X4  inches . $8.26 

87-127  BARIUM  PLATINO-CYANIDE  FLUOROSCOPE  AND  SCREEN,  5x7  inches . 16.80 

87-130  BARIUM  PLATINO-CYANIDE  FLUOROSCOPE  AND  SCREEN,  6X8  inches . 19.26 

87-140  CALCIUM  TUNGSTATE  FLUOROSCOPE  AND  SCREEN,  5  X  7  inches . 12.00 

87-145  CALCIUM  TUNGSTATE  FLUOROSCOPE  AND  SCREEN,  6X8  inches . 13.60 


No.  87-176 


87-176  PROTECTOR  for  X-Ray  Tube.  This  Protector  is  of  rubber  and  will  fit  over  all  sizes  of  tubes  up  to 

six  inches  in  diameter .  . $8.75 

87-180  PROTECTOR  for  large  X-Ray  Tubes.  This  Protector  is  made  of  glass  containing  approximately 

40  per  cent,  of  lead,  and  should  be  used  with  tubes  measuring  7  inches  and  8  inches  in  diameter  .  13.60 


No.  87-190 


87-190  EYE-GLASS  PROTECTOR  to  be  worn  by  operator  when  doing  X-Ray  work  .  . 


$3.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


90-10 

90-16 

90-20 

90-26 

90-30 

90-36 

90-40 

90-46 

90-60 

90-66 

90-76 

90-80 

90-96 

67-10 

90-100 

90-106 


3U 


ELECTRICITY 

ELECTRICAL  SUPPLIES 


COPPER  WIRE,  bare. 
B.  &  S.  Gauge  .  .  .  . 
Price  per  1  oz.  Spool 
Price  per  4  oz.  Spool 
Price  per  1  lb.  Spool  . 


COPPER  WIRE,  double  cotton  covered. 

B.  &  S.  Gauge . 

Price  per  4  oz.  Spool . 

Price  per  1  lb.  Spool . 

COPPER  WIRE,  enamel  coated. 

B.  &  S.  Gauge . 

Price  per  4  oz.  Spool . 


a 

b 

c 

d 

e 

f 

g 

h 

Fi 

16 

18 

20 

22 

24 

26 

27 

28 

[30 

$0.20 

$0.26 

.26 

.30 

.32 

.36 

.38 

.36 

$0.76 

.76 

.80 

.86 

.90 

.96 

1.00  1 

L.10 

>n  covered, 

paraffined. 

B.  &  S.  Gauge  No. 

18 

Per 

]/2  Pound  Coil 

$0.40 

Per  Pound  Coil 

a 

b 

c 

d 

e 

f 

g 

h 

i 

J 

16 

18 

20 

22 

24 

26 

27 

28 

30 

36 

$0.36 

.40 

.46 

.60 

.62 

.66 

.60 

1.16 

$0.90 

.96 

1.00 

1.06 

1.10 

1.36 

1.40  1 

L.60 

a 

b 

c 

$0.75 


28 

$0.86 


30 

1.36 


36 

1.96 


FLEXIBLE  WIRE,  TINSEL  WIRE,  covered  with  green  twisted  braid . Per  Yard 

LAMP  CORD,  two  conductors  twisted,  B.  &  S.  Gauge  No.  18,  rubber  and  cotton  insulation.  Per  Yard 
THEATRE  CABLE  for  40  amperes  current;  advisable  for  use  in  lantern  projection.  This  cable  con¬ 
sists  of  two  conductors,  flexible,  cotton  wrapped,  rubber  covered,  braided,  twisted  together  with 
filler,  and  finished  with  two  weather-proof  braids . Per  Yard 


SPRING  BRASS  WIRE. 

B.  &  S.  Gauge  .... 
Price  per  4  oz.  Spool  . 
FUSE  WIRE.  a 
Amperes  ... 

Price  per  yard  .  $0.07 


a 

22 

$0.30 
b  c 
1  3 


b 

24 

.32 

d 

5 


GERMAN  SILVER  WIRE, 

bare. 

B.  &  S.  Gauge  .... 

Price  per  4  oz.  Spool  . 


26 

$0.48 

IRON  PICTURE  WIRE,  No.  1 
LEAD  WIRE,  inch  diameter 


c 

27 

.36 
e 
10 

.18 

18  per  cent,  alloy, 

a  b  c 
28  30 

.64  .60 


.08  .10  .12 


d  e 
28  30 

.40  .60 

f  g 
15  35 

.26  .40 


$0.20' 

.20 


1.60 

alloy. 


90-60  GERMAN  SILVER  WIRE,  18  per  cent, 
single  cotton  covered. 

a  b  bb  c  d  dd 

B.  &.  S.  Gauge  .  .  18  20  24  28  30  36 

Price  per  4-oz.  Spool  $0.76  1.00  1.10  1.20  2.00 
Price  per  1  lb.  Spool  $1.76 
90-70  IRON  WIRE,  soft  drawn,  bare. 

abed 
B.  &  S.  Gauge  .  .  24  27  28  30 

Price  per  4  oz.  Spool  $0.16  .18  .19  .20 

. Per  Package  $0.10 

.  Per  Foot  .05 

SPECIAL  HIGH  RESISTANCE  WIRE  for  use  in  resistance  measurements,  —  especially  valuable  in 

determining  the  effect  of  temperature  on  resistance .  Per  10  feet  .25 

PIANO  WIRE,  best  quality  imported,  wound  in  coils,  each  weighing  approximately  pound. 

abed 

Diameter,  inch .  .028  .022  .0178  .014 

Per  Coil .  $0.40  .46  .46  .66 

PLATINUM  WIRE.  a  b  c  d  e  f 

B.  &  S.  Gauge .  20  22  24  26  28  30 

In  view  of  the  continual  market  fluctuations  in  the  price  of  Platinum,  we  quote  only  on  application. 

ZINC  WIRE,  %  inch  diameter . Per  Foot  $0.20 


312 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


90-150  ARTIFICIAL  LIGHT  CIRCUIT  for  reproducing,  within  the  laboratory,  conditions  similar  to  those  of 
an  actual  incandescent  lighting  circuit  as  worked  out  in  the  Applied  Electrical  Laboratory  of  Pratt 
Institute. 

A  wire  of  known  high  resistance  per  mil-foot,  resembling  in  appearance  an  ordinary  incandescent 
lighting  wire,  but  having  an  asbestos  insulation  to  avoid  danger  of  fire.  In  use  this. wire  is  strung 
along  the  side  of  a  room  or  mounted  on  a  movable  frame  using  standard  porcelain  insulators  and 
cleats,  lamp  sockets  and  switches. 

Fiftv-foot  Artificial  Lighting  Circuit  complete  with  special  resistance  wire,  sufficient  insulators,  cleats, 

lamp  sockets  and  switch,  with  full  directions  and  diagrams  for  setting  up . $8.76 


THE  IMPROVED  RAPID  BATTERY  CONNECTORS 


Patent  Pending 

Nos.  90-176  to  90-180 


As  will  be  suggested  from  the  cut,  these  battery  connectors  are  made  of  a  carefully  proportioned  spiral  spring 
o  fphosphor-bronze  wire,  the  proper  size  to  give  sufficient  rigidity  and  at  the  same  time  to  make  them  easy  of  connec¬ 
tion. 

The  spirals  being  separated  by  a  slight  pull,  the  straight  end  of  the  next  connector  is  readily  slipped  in  place, 
making  a  secure  electric  contact  which  will  not  accidentally  loosen  in  the  course  of  the  experiment. 

These  terminals  are  especially  serviceable  in  laboratory  work,  since  they  have  the  important  feature  of  being 
connected  with  equal  facility  to  either  an  English  or  American  form  binding  post.  For  parallel  or  multiple  connec¬ 
tion  they  are  equally  well  suited.  The  use  of  this  connector,  therefore,  does  away  with  the  multiplicity  of  connectors 
designed  for  meeting  the  conditions  of  various  kinds  of  binding  posts.  It  frequently  happens  that  one  type  of  instru¬ 
ment  having  an  English  post  has  to  be  connected  with  another  having  an  American  post.  With  the  usual  form  of 
connectors  this  condition  is  very  hard  to  meet.  With  the  “Rapid”  this  difficulty  is  entirely  overcome. 

Please  note  the  diagram  for  methods  of  connecting  to  English  posts,  to  American  posts,  and  for  connecting  in 
multiple  and  parallel  circuits. 

As  will  be  noted  from  the  listing  below,  these  connectors  are  furnished  in  pairs  or  in  quantity,  without  wire  con¬ 
nections,  also  furnished  with  wire  connections  of  varying  length. 


90-175 

90-177 


THE  IMPROVED  RAPID  CONNECTING  TIPS . . Per  Dozen  $0.25 

Per  Hundred  2.00 

THE  IMPROVED  RAPID  CONNECTORS,  attached  to  connecting  cord  6  inches  long,  especially 

designed  for  close  connection,  such  as  joining  batteries  in  multiple  and  in  series  .  .  .  Per  Pair  .20 


90-179  THE  IMPROVED  RAPID  CONNECTORS,  attached  to  a  con¬ 
necting  cord  2  feet  long . Per  Pair 

90-180  THE  IMPROVED  RAPID  CONNECTORS,  attached  to  a  con¬ 
necting  cord  3  feet  long . Per  Pair 

CONNECTORS 

90-185  THE  “PRIMO”  POSITIVE  CONTACT  LECTURE  TABLE 
CLASPS.  These  connectors  are  recommended  for  rapid  con¬ 
nections  in  lecture  table  work.  Connections  to  all  styles  of 
binding  posts,  both  bare  and  insulated  wire,  can  be  made  in  an 
instant.  The  grip  with  teeth  makes  an  excellent  contact 
even  through  heavily  insulated  wires . Per  Pair 

90-187  THE  “PRIMO”  POSITIVE  CONTACT  LECTURE  TABLE 
CONNECTOR.  Consists  of  a  pair  of  No.  90-186  Clasps  with 
a  4-foot  length  of  flexible,  heavily  insulated  copper  wire.  Each 


$0.30 


.40 


.60 


Nos.  90-186  to  90-187 


.80 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


3i3 


90-190 


* 


90-195 


90-220 


UNIVERSAL  CONNECTOR  TIP  adapted  to  both  English  and  American  types  of  binding  posts. 

To  make  a  convenient  laboratory  connector,  cut  a  single  connecting  flexible  cord  to  the  desired 
length.  Strip  the  insulation  for  one-half  inch  at  each  end,  leaving  the  bare  wires.  Twist  the  bared 
wires  between  the  fingers,  place  in  the  groove,  and  bend  over  with  a  vise  or  a  pair  of  pliers  until 
the  wire  is  pinched  firmly  between  the  poles  of  the  connector.  Some  prefer  to  touch  the  contact 
with  a  drop  of  solder  before  bending  over . Each  $0.05 


No,  90-195 


THE  CADY  HIGH  POTENTIAL  CONNECTOR 

THE  CADY  INSULATED  PINCH  CONNECTOR,  designed  for  high  potential  currents  to  insure 
safety  to  the  worker  and  to  guard  against  short  circuit. 

Every  instructor  and  wireless  worker  has  had  his  patience  tried  with  the  old-fashioned  wire  con¬ 
nectors.  They  waste  time,  they  fail  to  grip  the  smaller  sizes  of  wire  and  there  is  constant  danger 
of  short  circuit  and  a  ground  through  the  operator. 

The  Cady  Pinch  Connector  makes  all  these  troubles  vanish.  There  are  no  screws  to  turn,  only  a 
knob  to  press.  By  means  of  a  strong  spring  inside  the  connector,  a  good  contact  is  assured  with 
any  size  of  wire  from  %2-inch  diameter  to  the  thinnest  wires  and  ribbons.  The  connector  is  com¬ 
pletely  insulated,  being  encased  in  hard  rubber,  insuring  perfect  insulation  and  safety  in  use. 

These  advantages  make  the  Cady  Pinch  Connector  invaluable  for  general  experimental  work  and 
for  lecture  demonstration,  especially  when  frequent  changes  in  connections  have  to  be  made. 
For  connecting  the  fine  wires  of  vacuum  tubes  and  in  other  high  voltage  experiments  they  will  be 


found  indispensable . Price  Each  $0.95 

PORCELAIN  INSULATING  TUBE,  after  Fuller  and  Brownlee  (Experiment  74) . 12 


90-221  WOODEN  CORES  with  ATTACHED  BINDING  POSTS  for  above 


.25 


314 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


•f 


BINDING  POSTS,  CONNECTORS,  ETC. 


All  of  our  binding  posts,  connectors,  etc.,  are  manufactured  in  our  own  shop,  accurately  made  from  the  best 
material,  using  special  tools.  By  manufacturing  in  large  quantities  we  are  able  to  supply  them  at  prices  which  will 
compare  favorably  with  those  commonly  charged  for  similar  articles  of  inferior  material  and  workmanship.  We 
desire  to  emphasize  the  fact  that  all  binding  posts  leaving  our  factory  are  finished  handsomely,  polished  and  lacquered. 

When  ordering  binding  posts  state  whether  screws  and  washers  are  desired  or  not.  If  screws  are  wanted  state 
whether  wood  or  machine,  round  or  flat  headed,  and  length. 

At  an  additional  expense  of  one  cent  each  a  screw  of  any  kind  or  size,  together  with  either  one  or  two  washers, 
will  be  supplied. 

Each  article  herewith  illustrated  is  represented  full  size. 


No.  90-225 
Each  .  $0.90 


No.  90-230 
Each  .  $0.90 


No.  90-240 
Each  .  $0.55 


No.  90-242 
Each  .  $0.46 


No.  90-245 
Each  .  $0.58 


No.  90-247 
Each  .  $0.26 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


3i5 


No.  90-270 
Each  .  $0.46 


No.  90-290 
Each  .  $0.18 


No.  90-288 
Each  .  $0.12 


No.  90-284 
Each  .  $0.16 


No.  90-286 
Each  .  $0.12 


No.  90-306 
Platinum  Tipped 
Each  .  $0.76 

1MH 

wt  % 

gifc 

IHI  No.  90-312 

No.  90-296  No.  90-310  Each  .  $0.10 

Each  .  $0.16  Each  .  $0.11 


No.  90-297 
Each  .  $0.16 


Each  .  $0.26 


No.  90-299 
Each  .  $0.16 


No.  90-316  Triple  Connectors . Each  $0.18 

BATTERY  CARBON  BINDING  POSTS,  see  page  326. 


\ 


316 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


SWITCHES 


90-320  CONNECTION  BOARD,  after  Fuller  and  Brownlee  (Experiment  76) . $3.00 

90-326  SINGLE  POLE,  SINGLE  THROW  KNIFE  SWITCH,  15  amperes  at  125  volts,  mounted  on  porce¬ 
lain  base .  -56 

90-327  SINGLE  POLE,  DOUBLE  THROW  KNIFE  SWITCH,  15  amperes  at  125  volts,  mounted  on  porce¬ 
lain  base .  *65 

90-330  DOUBLE  POLE,  SINGLE  THROW  KNIFE  SWITCH,  15  amperes  at  125  volts,  mounted  on  porce¬ 
lain  base .  -66 

90-332  DOUBLE  POLE,  DOUBLE  THROW  KNIFE  SWITCH,  15  amperes  at  125  volts,  mounted  on  porce¬ 
lain  base .  *90 

90-336  DOUBLE  POLE,  DOUBLE  THROW  SWITCH,  capacity  50  amperes  at  250  volts,  heavy  construc¬ 
tion  for  lantern  work .  2.26 


No.  90-340  No.  90-362  No.  90-366 


90-340  POINT  SWITCH,  wood  base,  brass  terminals,  one  point . $0.18 

90-342  POINT  SWITCH,  wood  base,  brass  terminals,  two  point . .  .  .22 

90-360  ONE-POINT  RUBBER  BASE  SWITCH,  square  base,  with  binding  posts  on  front .  .80 

90-362  TWO-POINT  RUBBER  BASE  SWITCH,  square  base,  with  binding  posts  on  front .  .90 

90-364  THREE-POINT  RUBBER  BASE  SWITCH,  square  base,  with  binding  posts  on  front .  1.20 

90-366  FOUR-POINT  RUBBER  BASE  SWITCH,  square  base,  with  binding  posts  on  front .  1.46 

90-366  BATTERY  RHEOSTAT  AND  SWITCH,  suitable  for  regulating  miniature  battery  lamps,  speed  of 
small  motors,  etc. 

This  switch  consists  of  six  steps  mounted  on  a  polished  wood  base  with  hard  rubber  handle.  Total 

resistance  5  ohms;  trimmings  nickel-plated .  1.26 


90-370 


No.  90-376 


No.  90-380 


90-370  WOOD  PUSH  BUTTON,  excellent  quality,  hard  rubber  button,  hardwood  antique  oak  finish  .  .  $0.10 

90-376  DESK  PUSH  BUTTON,  for  %-inch  hole,  nickel-plated  trim,  light  pearl  button . 28 

90-380  METAL  PUSH  BUTTON,  hard  rubber  button,  ornamented  metal  case,  with  screw  holes.  Diameter 

2  inches .  -46 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


317 


No.  90-390  No.  90-392 


90-390  SINGLE  CONTACT  KEY,  hardwood  base,  open  circuit  key  with  two  binding  posts . $0.78 

90-392  DOUBLE  CONTACT  KEY,  hardwood  base,  open  circuit  with  pair  of  binding  posts  for  each  circuit  2.60 


No.  90-396 

90-396  DOUGLASS  UNIVERSAL  DOUBLE  CONTACT  KEY.  With  the  possible  exception  of  certain 
classes  of  condenser  measurements,  where  the  highest  insulation  is  required,  the  Douglass  Key 
will  be  found  to  be  absolutely  satisfactory. 

The  key  is  most  universal  in  character  as  is  shown  by  the  following  suggestions,  which  are  a  few 
of  the  uses  to  which  it  may  be  put. 

The  Douglass  Key  can  be  used, — 

1.  To  close  a  single  circuit. 

2.  To  open  a  single  circuit. 

3.  To  close  two  separate  circuits. 

4.  To  close  one  circuit  and  open  another  simultaneously. 

5.  To  open  one  circuit  and  close  another. 

6.  To  open  connection  with  one  circuit  and  close  to  a  second. 

7.  To  close  one  circuit,  open  the  second  and  close  the  third  in  one  movement. 

It  will  thus  be  noted  that  the  Douglass  Key  serves  about  every  possible  use  in  the  laboratory  with 

the  exception  of  high  capacity  condenser  work . $4.80 


No.  90-410 


90-410  HIGH  INSULATION  DOUBLE  CONTACT  KEY.  This  is  a  high-grade  key,  especially  designed 
where  extra  high  insulation  is  required.  Heavy  ebonite  blocks  and  base,  extra  large  binding  posts 
and  heavy  platinum  contact.  All  metal  parts  highly  polished  and  lacquered.  This  is  a  handsome 
and  serviceable  key  for  general  work . $12.00 


3i8 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


HIGH  TENSION  KEYS 


No.  90-430  No.  90-435 


The  following  keys  and  switches  are  recommended  whenever  one  has  occasion  to  use  high  voltages,  to  make 
high  resistance  measurements  or  accurate  tests  on  condensers  or  other  apparatus. 

They  are  mounted  on  bases  of  pure  ebonite,  and  where  pillars  are  used  the  pillars  also  are  of  pure  ebonite. 
Extreme  care  is  used  in  construction,  and  our  line  will  be  found  strictly  high  grade  in  every  respect.  The  leakage 


factor  is  very  low. 

90-415  SHORT  CIRCUIT  KEY . $12.00 

90-420  SINGLE  PLUG  SWITCH,  mounted  on  ebonite  pillars,  ebonite  handle,  spring  capped  plugs  to  prevent 

blocks  being  forced  apart  when  plug  is  inserted . 16.76 

90-425  LAMBERT’S  CAPACITY  TEST  KEY,  heavy  ebonite  blocks  and  pillars . 22.50 

90-430  RITCHIE  REVERSING  KEY . 24.50 

90-435  KEMPE’S  CHARGE  AND  DISCHARGE  KEYS,  ebonite  handles . 20.00 


No.  90-460 

90-460  INTERRUPTING  WHEEL  for  interrupting  a  current. 

It  is  frequently  desired  in  induction  experiments  to  interrupt  the  current  and  also  to  vary  the  speed 
of  the  interruption.  The  design  above  illustrated  consists  of  a  toothed  wheel  mounted  on  an 
axle  attached  to  the  uprights  on  a  neatly  polished  base.  A  spring  contact  arm  rests  against  the 
toothed  rim  of  the  wheel.  This  spring  contact  arm  is  in  electrical  connection  to  one  binding  post 
and  the  pillar  supporting  the  wheel  to  the  other.  If,  therefore,  connections  are  made  to  the  bind¬ 
ing  posts  the  current  will  be  interrupted  by  the  teeth  of  the  wheel  as  it  is  revolved  by  means  of  the 
crank.  These  interruptions  are  positive  and  the  instrument  is  used  to  advantage  connected  in 
series  with  the  primary  of  No.  96-40  Primary  and  Secondary  Coil . $1.90 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


319 


COMMUTATORS 


No.  90-470 


No.  90-485 


No.  90-490 


90-470  SIMPLE  MERCURY  CONTACT  POLE  CHANGER.  This  is  a  simple  standard  form  with  improved 

mercury  wells  and  contact.  Handsomely  finished  base  with  four  binding  posts . $0.65 

90-476  SPLIT  RING  POLE  CHANGER,  consisting  of  a  neatly  polished  wooden  base  on  which  are  mounted 
four  binding  posts  with  connected  contact  arms  which  make  contact  with  the  top  of  the  split  ring 
reversing  switch. 

This  switch  is  provided  with  a  neat  key-shaped  hard  rubber  piece.  All  metal  parts  neatly  polished 

and  lacquered .  I.75 

90-480  PALMER’S  PLUG  FORM  POLE  CHANGER.  This  form  consists  of  a  polished  base  on  which  are 
mounted  four  brass  curved  blocks,  each  block  provided  with  a  binding  post.  Current  reversal 
secured  by  changing  the  position  of  the  tapered  plugs  in  the  tapered  holes.  Brass  parts  neatly 

polished  and  finished .  2.90 

90-486  IMPROVED  BLOCK  HANDLE  POHL’S  COMMUTATOR.  The  simple  form  above  illustrated 
secures  positive  current  reversals  in  a  cleanly  and  efficient  manner.  The  design,  originated  in  our 
laboratories,  consists  of  a  polished  wooden  base  with  mercury  wells,  each  well  connected  to  a  bind¬ 
ing  post  with  a  non-detachable  top.  The  pole  changer  is  of  the  rocking  type,  securing  instant 
current  reversal  by  merely  tipping  from  one  pair  of  mercury  wells  to  the  other.  All  metal  parts 

are  handsomely  polished  and  lacquered .  1.90 

90-490  KNIFE  SWITCH  POLE  CHANGER,  mounted  on  slate  base  with  visible  connections.  Will  carry  15 

amperes .  1.65 


No.  90-480 


No.  90-475 


No.  90-525 


90-546 


90-525 


ELECTRIC  BELLS 


DISSECTIBLE  IRON  BOX  BELL.  It  will 
ring  satisfactorily  with  one  cell  of  battery 
and  will  not  stick  or  buzz  with  six  cells 
connected.  The  cover  is  of  light  pressed 
steel,  neatly  japanned.  A  slight  pressure 
of  the  fingers  on  each  side  of  the  cover  will 
disengage  it  from  the  clamps  opening  to 
view  the  entire  mechanism.  Gong  2)4 
inches  in  diameter .  . $0.45 


DISSECTIBLE  IRON-CLAD  BUZZER.  The  No-  90-665 

buzzer  listed  under  this  number  is  in  ap¬ 
pearance  the  same  as  No.  90-625  Bell,  without  the  gong,  gong  extension 
and  striking  rod . $0.65 


90-666  SIX-INCH  IRON-CLAD  WATER-PROOF  GONG.  This  iron-clad  bell  is  designed  and  constructed 
to  protect  the  operating  mechanism  and  magnets  from  dampness,  dust,  and  other  outside  influ¬ 
ences.  The  end  of  the  striking  rod  is  the  only  part  of  the  working  mechanism  not  contained 
inside  the  case  and,  as  this  is  operated  in  a  straight  line,  the  opening  in  the  case  is  very  small  and 
securely  protected.  The  contact  points  are  of  hardened  carbon,  which  permits  of  the  use  of  a 
current  ranging  from  4  to  150  volts  with  magnets  wound  for  proper  resistance.  The  vibrations 
are  strong,  rapid,  and  regular. 

Iron-Clad  Water-proof  Gong,  resistance  5  ohms,  gong  6  inches  in  diameter .  6.25 


320 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


BATTERIES 


No.  91-15 


GILLEY-SKIDMORE  BATTERY 

91-10  PORCELAIN  MOUNTED  GILLEY-SKIDMORE  BATTERY  STAND  for  the  study  of  the  various 

phenomena  of  the  voltaic  cell.  This  stand  has  been  used  for  a  number  of  years  and  its  extensive  sale 
has  been  sufficient  recommendation  for  it.  It  will  be  seen  that  the  stand  consists  essentially  of  a 
recessed  porcelain  base  with  upright  support.  To  the  upright  are  fastened  the  two  swiveled  arms 
bearing  the  clamps.  To  these  arms  may  be  attached  various  accessories  for  the  study  of  character¬ 
istics  of  different  types  of  cells  and  also,  in  formulating  the  laws  governing  the  action  and  efficiency 
of  a  simple  single  or  two-fluid  cell.  This  form  of  Students’  Battery  Outfit  is  recommended,  since 
the  wire  leads  are  attached  to  the  binding  posts  on  the  top  of  the  stand,  which  has  a  broad  base 
and  hence  avoids  the  tipping  over  of  the  battery  which  occurs  in  other  types. 

This  cell  is  admirably  adapted  for  its  purpose  and  excels  in  simplicity  of  construction  the  much  more 
expensive  and  bulky  commercial  cells.  In  the  study  of  the  leading  types  of  batteries  various 
accessories  may  be  used  to  set  up  the  complete  cell.  The  cell  is  particularly  adapted  for  the  study  of 
polarization,  internal  resistance,  effects  of  different  solutions,  etc.,  and  readily  adapts  itself  to  the 
construction  of  the  Electro-motive  Series.  All  parts  are  neatly  finished  and  the  battery  presents  a 


pleasing  appearance  in  any  laboratory. 

Porcelain  mounted  Gilley-Skidmore  Battery  Stand  only,  without  any  accessory  parts . $1.20 

91-12  PORCELAIN  MOUNTED  GILLEY  SKIDMORE  DEMONSTRATION  CELL,  complete  with  jar, 

copper,  and  zinc  element  for  study  of  simple  single  fluid  cell .  1.40 

91-15  PORCELAIN  MOUNTED  GILLEY  SKIDMORE  BATTERY  STUDY  OUTFIT.  Consists  of  stand 

complete  with  all  the  accessories  listed  below .  2.40 

SEPARATE  PARTS 

91-15a  JAR . $0.06 

91-16b  POROUS  CUP,  3  X  7.5  centimeters  inside  diameter .  .15 

91-15c  ZINC  PENCIL,  %  inch  diameter . 11 

91-15d  CARBON  PENCIL,  %  inch  diameter . 11 

91-16e  ZINC  ELEMENT,  right  angle  stem . 08 

91-16f  COPPER  ELEMENT,  right  angle  stem . 08 

91-15g  IRON  ELEMENT,  right  angle  stem . 07 

91-15h  ALUMINUM  ELEMENT,  right  angle  stem . 10 

91-16i  LEAD  ELEMENT,  right  angle  stem . 07 

91— 15j  PURE  BLOCK  TIN  ELEMENT,  right  angle  stem . 20 

91-16k  COPPER  CYLINDRICAL  ELEMENT . 25 

91-26  TURNER  AND  HERSEY  TAPERING  ZINC  ELEMENT  for  use  with  above  outfit  in  the  study  of 

polarization .  .08 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


321 


The  GILLEY  SKIDMORE  BATTERY  STAND,  with  its  porcelain  base  and  swiveled  arms,  overcomes  the 
many  inconveniences  encountered  in  the  following  designs  which  we  offer  to  meet  the  demands  of  individual  teach¬ 
ers.  If  the  following  designs  are  best  adapted  to  individual  needs,  we  wish  to  assure  customers  that  the  quality 
of  material  and  workmanship  is  above  question.  We  unhesitatingly  recommend,  however,  our  PORCELAIN 
MOUNTED  SKIDMORE  OUTFITS. 


No.  91-30  Porous  Cup  of  No.  91-35  No.  91-42 


91-30  GOTHAM  DEMONSTRATION  CELL.  Consists  of  a  Rectangular  Glass  Jar  with  a  millimeter 
scale  etched  on  the  front  for  convenience  in  measuring  the  separation  of  the  elements.  The 
element  holders  are  of  non-corrosive  metal  and  are  cast  in  a  most  convenient  shape  for  resting 
on  the  jar  and  for  clamping  and  adjusting  the  elements. 

Complete  with  a  Copper  and  Zinc  Element  for  study  of  a  simple  single  fluid  cell .  $1.40 

91-35  GOTHAM  DEMONSTRATION  BATTERY  STUDY  OUTFIT.  Consists  of  the  Rectangular  Jar 
with  ruled  front,  a  pair  of  non-corrosive  metal  Element  Holders  and  the  Zinc  and  Copper  Elements 
of  above  cell,  with  the  addition  of  a  special  Rectangular  Porous  Cup,  round  Carbon  and  Zinc 
Elements  and  flat  Elements  of  Aluminum,  Carbon,  Copper,  Iron,  Lead,  Nickel  and  Tin. 

Complete . • .  2.10 

91-40  HALL’S  IMPROVED  DEMONSTRATION  CELL.  In  this  design,  we  have  discarded  the  construc¬ 
tion  using  a  metal  cap  for  the  jar,  now  using  a  neat  porcelain  cap  moulded  to  fit  the  rim  of  the 
jar.  To  this  porcelain  cap  are  attached  the  special  arms  which  bear  the  clamps.  These  clamps 
wdll  hold  either  the  round  or  flat  elements.  The  method  of  mounting  to  the  porcelain  cap  permits  of 
adjusting  the  distance  of  the  two  elements  at  will. 

Jar,  Porcelain  Cap  with  attached  Bracket  and  Clamps  and  Zinc  and  Copper  Elements  for  study  of 


a  simple  single  fluid  cell .  .  .  -66 

91-42  HALL’S  IMPROVED  DEMONSTRATION  BATTERY  STUDY  OUTFIT.  Complete  with  all 

accessories  listed  below,  including  the  special  copper  cylindrical  element. 

Complete  . .  1-65 

ACCESSORIES 

91-43  JAR .  $0.06 

91-44  POROUS  CUP,  inside  measurements  3  X  7.5  centimeters .  .15 

91-45  ZINC  PENCIL . 11 

91-46  CARBON  PENCIL . 11 

91-47  ZINC  ELEMENT,  flat . 06 

91-48  COPPER  ELEMENT,  flat . 05 

91-49  LEAD  ELEMENT,  flat  . 06 

91-60  IRON  ELEMENT,  flat . 05 

91-61  ALUMINUM  ELEMENT,  flat . 05 

91-62  TIN  ELEMENT,  flat . 11 

91-53  COPPER  CYLINDRICAL  ELEMENT . 26 

91-64  CARBON  ELEMENT,  flat .  -11 


322 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  91-75 


91-65  LECLANCHE  BATTERY,  especially  adapted  for  “open  circuit”  work,  most  frequently  used  in  bell 
service.  E.  M.  F.  about  1.4  volts. 

Cell  complete . . 

91-67  POROUS  CUP,  sealed . 

91-68  ZINC  PENCIL,  with  binding  screw . .  . 

91-69  JAR . . 

91-75  GALLON  STANDARD  DANIELL  CELL.  This  cell  has  attained  the  position  of  a  standard  labora¬ 
tory  cell,  being  readily  adapted  to  all  kinds  of  circuit  work.  Its  E.  M.  F.  is  about  1.08  volts,  this 
voltage  remaining  constant  throughout  the  life  of  the  cell.  For  this  reason  it  may  be  seen  that  it 
is  of  great  value  for  work  in  electrical  experiments. 

Cell  complete,  one  gallon  size,  including  Jar  and  Porous  Cup,  special  Copper  Cylinder  with  holder,  and 

Zinc  Element . 

31-265C  JAR  . .  ...  .  . 

91-77  POROUS  CUP . 

91-79  ZINC  ELEMENT . 

91-80  COPPER  CYLINDER . . 

91-90  QUART  STUDENTS’  DANIELL  CELL,  complete,  including  jar  not  illustrated . 

91-92  POROUS  CUP,  2X4  inches . \  . 

91-94  ZINC  ELEMENT  WITH  BINDING  POST . 

91-96  COPPER  ELEMENT . 

31-266b  JAR . .' . 


$0.75 

.40 

.10 

.25 


2.60 

.40 

.25 

1.10 

.95 

.95 

.20 

.35 

.15 

.25 


No.  91-105 


No.  91-120 


91-105 


91-120 


CROW  FOOT  GRAVITY  CELL,  one  of  the  most  popular  closed  circuit  cells,  very  largely  used  by 
telegraph  and  telephone  companies,  gallon  size,  complete 
91-107  ZINC  ELEMENT,  crow  foot  type’ 

91-110  COPPER  ELEMENT  ...  . 

3i-266c  jar . ;;;;;;;;;;;;;;;;;;;;;;; 

IMPROVED  FULLER  CELL,  for  general  laboratory  service,  open  or  closed  circuits.  This  cell  has 
unusually  high  E.  M.  F.,  about  2.4  volts,  with  internal  resistance  of  .4  ohm,  gallon  size  complete. 
91-122  POROUS  CUP,  3X7  inches 
91-124  ZINC  ELEMENT  .  . 

9i-i35  carbon  cylinder.  .  .  .  ‘  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ; 

31-265c  JAR,  6X8  inches . 


'2.10 

1.40 

.30 

.40 


2.65 

.C5 

1.20 

.80 

.40 


mms* 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


323 


91-166  BUNSEN  CELL,  a  two-fluid  cell  for  “open  circuit”  work.  E.  M.  F.  approximately  1.9  volts, 
internal  resistance  about  1.8  ohms. 

Bunsen  Cell  complete,  one  quart  size . 

91-166  JAR,  4 K  X  4 y2  inches  . 

91-167  POROUS  CUP,  iy2  X  5  inches  . 

91-169  ZINC  ELEMENT,  special  shape  with  binding  post  . 

91-170  FLUTED  CARBON  ELEMENT,  with  connector  and  binding  post . 

91-180  GRENET  BATTERY,  especially  adapted  for  experimental  and  demonstrative  work.  This  battery 
occupies  little  space  and  furnishes  a  powerful  current  for  a  short  time.  E.  M.  F.  is  approxi¬ 
mately  2  volts  at  the  start  with  very  small  internal  resistance. 

A  further  advantage  of  this  type  of  cell  is  that  the  zinc  element  may  be  raised  from  the  fluid,  thus 
stopping  action  of  the  cell,  and  preserving  the  strength  of  the  solution. 

One-pint  size  complete . 

91-182  ZINC  ELEMENT . . 

91-184  CARBON  ELEMENT . 

91-186  JAR  . 

91-190  GRENET  BATTERY,  similar  to  above,  but  one-quart  size,  complete . 

91-192  ZINC  ELEMENT . . 

91-194  CARBON  ELEMENT . 

91-196  JAR . 


91-206  GRENET  BATTERY,  similar  to  above,  but  two-quart  size,  complete 

91-207  ZINC  ELEMENT . 

91-209  CARBON  ELEMENT . 

91-210  JAR . 


91-246  FOUR-CELL  STUDENTS’  PLUNGE  BATTERY.  This  is  a 
simple  combination  of  Chromic  Acid  Cells  provided  with  ad¬ 
justing  features  which  permit  of  lifting  one  or  more  cells  from 
the  solutions.  It  may  be  used  to  advantage  on  the  demonstra¬ 
tion  table,  but  has  been  designed  particularly  for  students’ 
experiments. 

Complete  as  illustrated,  four-cell  type . . 

91-247  TWO-CELL  STUDENTS’  PLUNGE  BATTERY,  similar  to 
above,  but  arranged  for  two  cells  oaly . 

91-260  COMPLETE  ELEMENT,  including  two  carbons 
and  one  zinc  element  with  all  connections . 

91-262  CARBON  ELEMENT . 

91-264  ZINC  ELEMENT . 

31-265a  SPECIAL  BATTERY  JAR  . . 


$2.20 

.60 

.26 

1.26 

.20 


2.10 

.26 

.26 

.95 

2.76 

.28 

.36 

1.16 

4.20 

.36 

.50 

1.75 


6.50 

4.16 

1.45 

.26 

.40 

.12 


No.  91-246 


324 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


91-225 


91-227 


No.  91-225 

SIX-CELL  HIGH  SCHOOL  PLUNGE  BATTERY.  Perhaps  no  source  of  current  for  lecture  table 
or  general  laboratory  work  has  become  so  desirable  as  that  furnished  by  the  Chromic  Acid  Cell. 
In  the  design  illustrated  above  may  be  noted  a  form  of  portable  cell  which  has  found  great  favor 
throughout  the  country.  Each  cell  is  a  unit  in  itself  delivering  about  2  volts  and  very  powerful 
current  for  a  short  time.  One  or  more  may  be  combined  in  series  or  parallel  to  give  a  large  E.  M.  F. 
or  amperage. 

The  type  is  arranged  so  that  from  one  to  six  cells  may  be  used  as  desired.  All  six  may  be  placed  at 
one  time  in  the  solution.  If  it  is  desired  that  only  four  be  used,  as  above,  two  may  be  suspended 
to  the  cross  rod. 

This  battery  is  substantially  made,  provided  with  every  convenience  for  safe  use,  and  will  be  found 
indispensable  when  once  used. 

Complete  as  illustrated,  arranged  for  six  cells  . 

FOUR-CELL  SCHOOL  PLUNGE  BATTERY,  same  as  above,  but  arranged  for  four  cells  .  .  . 

91-229  COMPLETE  ELEMENT,  including  top,  two  carbon,  and  zinc  elements  . 

91-231  CARBON  ELEMENT . 

91-233  ZINC  ELEMENT . .  ,  .  .  ; 

91-235  SQUARE  BATTERY  JAR . , . ,  .' .  . 


$27.40 

19.76 

3.00 

.30 

1.30 

.45 


83-260  WATER  BATTERY,  50  cells,  mounted  on  substantial  neatly  finished  wooden  base. 

This  battery  is  particularly  adapted  to  advanced  work  when  high  voltage  and  low  amperage  are 

desired.  It  will  be  found  a  most  serviceable  battery  for  all  electrostatic  and  electrometer  work  .  $6.25 


83-252  - ,  same  as  above,  but  comprising  100  cells.  This  battery  is  a  combination  of  two  of  the  above  .  12.75 


A*  >>•« 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


325 


. 


No.  91-280 


No.  91-300 


91-280  MOUNTED  H-FORM  STANDARD  CELL.  This  cell  is  furnished  appropriately  mounted  on  base 
provided  with  binding  posts.  It  is  designed  that  students  may  assemble  their  own  cells. 

Complete  as  illustrated  . . 

91-282  H-FORM  STANDARD  CELL,  same  as  above  but  unmounted,  glass  part  only  with  sealed-in  plati¬ 
num  electrodes . 

91-300  DRY  CELL.  In  our  seventeen  years’  experience  we  have  experimented  with  a  great  number  of  dry 
cells.  For  length  of  life,  high  electro-motive  force,  and  low  internal  resistance  we  believe  that  the 
cell  illustrated  above  is  unexcelled.  It  polarizes  slowly  and  recovers  rapidly.  We  have  no  hesi¬ 
tancy  in  recommending  its  use  for  general  laboratory  work . 

STORAGE  BATTERIES 


Nos.  91-325  to  91-330 


Nos.  91-335  to  91-350 


91-315  MOUNTED  LEAD  PLATES  after  Millikan  and  Gale.  Fig.  277  . Pair 

91-325  STORAGE  BATTERY,  LEAD-LEAD  TYPE.  The  plates  measure  3J4  inches  square,  and  the  glass 
jar  is  byi  inches  high.  The  cell  has  a  capacity  of  six  ampere  hours  at  an  E.  M.  F.  of  two  volts  . 

91-330  -  — ,  same  as  above,  but  a  much  larger  cell,  and  is  recommended  for  such  work  as  operating  Ruhm- 
korff  coils,  performing  electrolysis  experiments,  and  other  laboratory  work  where  a  heavy  current 
is  necessary.  The  lead  plates  measure  7j^  inches  square  and  are  contained  in  a  glass  jar 
inches  high  X  9  inches  wide  X  3^  inches  deep.  The  capacity  of  each  cell  is  36  ampere  hours  at 

an  E.  M.  F.  of  two  volts . 

We  recommend  either  three  or  four  cells  as  the  proper  laboratory  outfit. 

91-336  PORTABLE  STORAGE  BATTERY,  enclosed  in  wooden  case  as  shown  in  the  illustration.  Capacity 
60  ampere  hours  at  an  E.  M.  F.  of  six  volts . 

91-340  -  — ,  same  as  above,  capacity  80  ampere  hours  at  an  E.  M.  F.  of  six  volts  . 

91-345  -  — ,  same  as  above,  capacity  100  ampere  hours  at  an  E.  M.  F.  of  six  volts . 

91-360  —  — ,  same  as  above,  capacity  80  ampere  hourg  at  an  E.  M.  F.  of  eight  volts . 


$2.30 

1.75 

.40 


$1.50 

2.15 

6.76 

21.00 

27.25 

32.50 

36.00 


326 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


BATTERY  SUPPLIES 

31-265  BATTERY  JARS,  of  excellent  quality. 

a  bed 

Size,  inches .  2)4  X  3)4  4X5  6X8  8X  12 

Each .  $0.12  .25  .40  1.60 

91-380  RECTANGULAR  BATTERY  JARS,  of  excellent  quality. 

a  b 

Size,  inches .  2)4  X  4 )4  X  7 

Each .  $0.35 


No.  90-185 

91-410  CARBON  AND  ZINC  BATTERY  CONNECTORS. 

a  b  c 

For  plates .  )4  to  %  %  to  K  K  to  1)4  inches 

Each .  $0.20  .35  .42 

THE  IMPROVED  RAPID  BATTERY  CONNECTORS 

(For  description  see  page  312) 

90-176  THE  IMPROVED  RAPID  CONNECTING  TIPS . Per  dozen 

Per  hundred 

90-177  THE  IMPROVED  RAPID  CONNECTORS,  a  six-inch  flexible  cord  with  a  Connecting  Tit 

No.  90-176  at  each  end . Eacl 

90-179  - ,  a  two-foot  flexible  cord  with  a  Connecting  Tip  No.  90-175  at  each  end . Each 

90-180  - ,  a  three-foot  flexible  cord  with  a  Connecting  Tip  No.  90-175  at  each  end . Each 

90-185  THE  “PRIMO”  POSITIVE  CONTACT  LECTURE  TABLE  CLASPS.  (For  description  see  page 

312.) . Per  Pair 

90-187  THE  “PRIMO”  POSITIVE  CONTACT  LECTURE  TABLE  CONNECTOR,  a  four-foot  flexible 

cord  with  a  Clasp  No.  90-186  at  each  end . Each 

90-190  UNIVERSAL  CONNECTOR  TIP  for  either  the  English  or  American  Binding  Post.  (See  page  313.) 

Each 

90-196  CADY  INSULATED  CONNECTOR  (See  page  313) . Each 


$0.26 

2.00 


.20 

.30 

.40 

I 

.60 

.80 

| 

.06 

.96 

No.  91-410a 


No.  91— 410b 


No.  91-410c 


Nos.  90-185  to  90-187 


No.  90-195 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


327 


ELECTRO-MAGNETISM 


92-15  AMPERE’S  LAW  STAND,  a 

convenient  stand  with  clamp 
for  holding  a  No.  10  copper 
conducting  rod;  with  shelf  for 
arranging  small  compasses 
about  the  conductor  and  bind¬ 
ing  posts  for  connecting  the 
lead  wires. 


No.  92-15 


92-17  AMPERE’S  LAW 


Full  directions  for  the  experi¬ 
ment  will  be  found  in  the 
National  P  h  ys  ic  s  Direction 
Sheets,  Experiment  E041,  a 
copy  of  which  will  be  furnish¬ 
ed  with  each  instrument  .  .  . 
APPARATUS  (Fuller  &  Brownlee,  Exp. 


$1.45 

81). 


No.  92-17 

Complete  as  illustrated  with 


four  ssaled-in  exploring  compasses,  but  without  the  larger  movable  magnetic  compass 


$2.65 


No.  92-20 


No.  92-30 


92-20  OERSTED’S  LAW  APPARATUS,  for  study  of  magnetic  action  of  currents  and  formulating  Ampere’s 

rule. 

This  apparatus  consists  of  a  base  to  which  are  mounted  two  pillars,  each  provided  with  two  binding 
posts,  one  each  for  the  terminals  of  the  parallel  conducting  wires.  A  sensitive  magnetic  needle 
separately  mounted  on  a  base  of  its  own  is  readily  adjusted  so  that  its  point  of  support  comes  mid¬ 
way  between  the  parallel  wires.  This  mounted  magnetic  needle  is  our  No.  81-12  and  will  not  be 

required  if  already  a  part  of  the  equipment .  $2.85 

92-22  OERSTED’S  LAW  APPARATUS  FRAME,  only  without  mounted  magnetic  needle .  2.25 

81-12  MOUNTED  MAGNETIC  NEEDLE,  as  used  in  No.  92-20  . 60 

92-30  HELIX  OERSTED’S  LAW  APPARATUS,  for  a  study  of  the  directive  action  which  a  fixed  current 
exerts  at  a  distance  on  a  magnetic  needle,  and  for  formulating  Ampere’s  Rule.  This,  our  adjustable 
needle  and  adjustable  helix  design,  consists  of  a  rectangular  metal  frame  mounted  as  illustrated 
on  a  polished  wooden  base.  The  upright  parallel  sides  of  this  frame  are  slotted  to  carry  the  holders 
for  the  movable  needle  and  for  the  helix.  That  a  study  of  the  effect  of  a  current  through  a  helix 
on  a  magnetic  needle  may  be  noted,  the  holders  of  the  helix  are  provided  with  a  pair  of  binding 
posts,  one  on  each  end.  A  pair  of  binding  posts  is  also  furnished  for  connecting  a  current  to  the 
rectangular  frame.  Two  fixed  needles,  one  over  the  upper  part  of  the  frame  and  one  within  the 
frame  over  the  under  side,  and  a  movable  needle  which  may  be  fixed  in  any  position  within  the  frame 
indicate  the  directive  action  of  a  current  on  a  magnetic  needle. 

All  metal  parts  of  this  apparatus  are  finely  polished  and  lacquered  and  the  needles  are  delicately 
balanced  on  steel  pivot  points. 

Complete  as  illustrated,  with  three  needles  and  helix  attachment  .  6.60 

92-36  SIMPLE  ADJUSTABLE  NEEDLE  OERSTED’S  LAW  APPARATUS.  This  design  is  essentially 
the  same  as  illustrated  and  described  above.  It  is,  however,  furnished  without  the  helix  attach¬ 
ment  and  without  the  two  fixed  needles.  As  may  be  readily  noted,  by  means  of  this  movable 
needle,  the  holder  movable  in  height  and  the  needle  movable  along  the  holder,  practically  any  posi¬ 
tion  within  and,  if  desired,  outside  the  frame  may  be  secured .  3.76 

92-37  HELIX  ATTACHMENT,  for  attachment  to  above  frame  in  study  of  the  directive  action  of  a  current 
through  a  helix  upon  a  magnetic  needle. 

This  attachment  is  provided  with  clamps  for  instant  clamping  to  the  slotted  upright  parallel  sides  of 

the  frame . . .  .85 

92-40  BAR  OF  IRON  and  BAR  OF  WOOD,  for  placing  within  helix  attachment  above  for  a  study  of  the 

magnetic  effects  produced  . Per  Pair  .16 


328 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


AMPERE’S  LAW 


92-50  AMPERE’S  FRAME,  illustrating  various  phenomena  due  to  the  magnetic  effects  of  an  electric  current. 

The  design,  improved  in  many  ways  incapable  of  illustration,  consists  essentially  of  a  base  to  which 
are  mounted  two  metal  uprights.  At  the  tops  of  these  uprights  are  attached  arms  carrying  at  their 
extremities  two  steel  cups  for  mercury  in  which  are  placed  the  pivoting  points  of  an  improved  sus¬ 
pension  device  carefully  balanced  by  means  of  a  metal  ball  and  provided  with  sockets  and  binding 
screws  for  attaching  the  different  contact  frames. 

These  frames  are  designed  to  illustrate  in  a  satisfactory  manner  several  interesting  and  instructive 
phenomena,  each  frame  interchangeable  in  the  suspension  device.  Five  frames  are  furnished,  —  a 
loop,  a  rectangle,  an  astatic  rectangle,  a  rectangular  coil,  and  a  solenoid.  In  addition  there  is 
furnished  a  suspension  frame  for  a  bar  magnet  and  a  soft  iron  rod. 

Perhaps  no  single  piece  of  apparatus  designed  for  the  study  of  magnetism  has  such  wide  application 
as  does  this  time-honored  Ampere’s  frame.  Results  are  strikingly  illustrated  with  the  minimum  of 
annoyance.  In  our  design  we  have  endeavored  to  obviate  the  previous  sources  of  difficulty  in  the 
old  forms  and  are  enabled  by  our  many  improvements  to  guarantee  satisfactory  results. 

The  design  is  capable  of  demonstrating  in  a  positive  manner: 

1.  Mutual  Action  of  Magnets  and  Solenoids. 

2.  Action  of  Currents  on  Solenoids. 

3.  Directive  Action  of  the  Earth  on  Solenoids. 

4.  Directive  Action  of  Magnets  on  Currents. 

5.  “Sucking  Effects”  of  Solenoids. 

6.  Action  of  a  Current  on  a  Pivoted  Magnet. 

Apparatus  complete,  as  illustrated,  including  all  accessories  described  above . 


92-60  FLOATING  HELIX  AND  CELL,  for  demonstrating 
the  magnetic  polarity  of  an  electro  magnetic 
solenoid. 

This  apparatus  consists  of  a  small  cell,  the  leads  of 
which  are  formed  into  a  horizontal  solenoid.  In 
use  the  elements  are  placed  into  the  small  jar  held 
in  a  disc  of  cork,  and  the  whole  placed  in  a  jar  of 
water  where  the  combination  will  float  upright. 
The  solenoid  will  soon  take  a  position  so  that  the 
axes  will  point  true  North  and  South.  From 
further  tests  with  a  bar  magnet  it  will  be  noted 
that  the  solenoid  will  act  the  same  as  a  magnetic 
needle,  one  end  developing  South  and  the  other 
North  polarity. 

Cell  complete  as  illustrated . 


$11.00 


1.60 


No.  92-60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


329 


PARALLEL  CURRENT 
APPARATUS 


No.  80-306  No.  80-310 

80-306  P/filALLEL  CURRENT  APPARATUS,  for  illustrating  mutual  actions  of  parallel  currents.  The 
design  consists  of  an  insulated  stand  to  the  head  of  which  are  attached  binding  posts  in  electri¬ 
cal  connections  with  two  bent  copper  wires.  To  these  bent  wires  are  suspended  two  small 
straight  copper  rods  cut  to  the  proper  length,  which  will  allow  their  free  ends  to  extend  within 
the  mercury  well  set  in  the  base. 

In  use  it  is  always  best  to  amalgamate  the  ends  of  these  copper  rods.  Success  of  the  experiment 
depends  also  upon  allowing  the  rods  to  just  make  contact  with  the  surface  of  the  mercury. 

Parallel  currents  flowing  in  the  same  direction  may  be  secured  by  connecting  both  binding  posts 
with  one  pole  of  the  battery;  the  other  pole  should  be  connected  to  a  binding  post  (not  shown  in 
illustration)  fastened  to  the  base  and  in  electrical  connection  with  the  mercury  well. 

Parallel  currents  running  in  opposite  directions  may  be  obtained 
by  simply  connecting  the  battery  terminals  and  the  binding 
posts,  at  the  top. 

In  the  first  case,  repulsion  of  the  wires  will  be  noted;  in  the  sec¬ 
ond,  attraction . 

80-310  CONTRACTING  HELIX,  illustrating  the  mutual  action  of  cur¬ 
rents. 

This  apparatus  consists  of  a  spiral  of  copper  wire,  one  end  of 
which  is  suspended  from  a  rigid  arm,  the  other  end  free  to  dip 
into  a  well  of  mercury  located  in  the  base.  If  current  is  allowed 
to  flow  through  the  spiral,  attraction  between  the  convolutions 
causes  the  coil  to  contract,  and  the  end  to  be  lifted  out  of  the 
cup  of  mercury,  thus  breaking  the  circuit  when  current  and  at¬ 
traction  cease,  and  the  wire  dips  again  into  the  mercury.  A 

rapid  and  vibratory  motion,  therefore,  is  produced . 

92-76  PARALLEL  CURRENT  REPULSION  COILS  with  BIFILAR 
SUSPENSION,  designed  to  teach  the  mutual  influence  of  par¬ 
allel  currents  and  self-induction.  One  of  the  coils  when  used 
separately  is  well  adapted  for  experiments  on  the  Earth’s  Mag¬ 
netic  Field. 

The  apparatus  consists  of  two  carefully  constructed  form-wound 
coils  of  1000  turns  double  cotton  covered  copper  wire.  Each 
coil  is  taped,  shellaced  and  baked.  Provided  with  binding 
posts  for  bifilar  suspension. 

As  the  illustration  indicates,  the  coils  are  suspended  by  an  ad¬ 
justable  clamp  fitting  a  vertical  rod  of  from  13  to  19  millimeters 
in  diameter,  the  clamp  being  so  designed  that  the  distance  be¬ 
tween  the  coils  may  be  varied  at  will.  Connections  to  the  coils 
from  the  clamp  are  such  that  they  are  readily  joined  either  in 
multiple  or  in  series  according  to  the  current  available.  The 
coils  are  wound  for  resistance  to  take  110  volt  direct  current 
when  running  in  series. 

Price  complete  without  stand . 

Note.  When  one  of  these  coils  is  used  for  experiments  in  Earth  Induction,  we  recommend  the  use  of  our  Lecture  Table  Galvanometer 
No.  93-130. 

92-77  COIL  FOR  MAGNETIC  INDUCTION.  A  form  wound  coil  with  connectors  and  flexible  leads. 

When  the  single  coil  is  connected  in  series  with  any  sensitive  galvanometer,  interesting  experi¬ 
ments  showing  the  earth’s  magnetic  field  and  other  induction  phenomena  may  be  performed. 

The  purchase  of  complete  apparatus  as  described  above  (No.  92-76)  for  demonstrating  also 
mutual  and  self  induction  is  recommended . $2.70 


330 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


ELECTRO-MAGNETS 


Figs.  7  8 

Nos.  92-110  to  92-130 


9 


92-100  STUDENTS’  ELECTRO-MAGNET,  simple  electro-magnet  capable  of  complete  demonstration  of 

magnetic  induction .  $0.65 

92-110  GILLEY  INDUCTION  COILS,  mounted  with  binding  posts. 

These  coils  are  designed  for  students’  use  in  the  study  of  Induction  and  Electro-magnetism.  Care¬ 
fully  prepared  students’  directions  for  their  use  will  be  found  in  the  Turner  and  Hersey  series  of 
experiments,  E042,  E150  and  E153.  Copies  of  these  experiment  sheets  are  furnished  with  each 
pair  of  coils. 

As  the  illustration  indicates,  the  coils  are  form-wound,  shellaced  and  baked  so  as  to  make  a  rigid  unit 
and  mounted  on  a  conveniently  designed  wood  base  with  binding  posts,  the  form  of  the  base 
being  such  as  to  permit  the  greatest  freedom  of  use  in  the  experiments  for  which  they  are  intended. 

The  hole  in  the  center  is  of  the  correct  size  to  take  the  soft  iron  armature  in  the  study  of  electro¬ 
magnets.  Sold  by  the  pair  only . Per  Pair  1.40 


ACCESSORY  APPARATUS  FOR  THE  STUDY  OF  INDUCTION  AND 
ELECTRO-MAGNETS  USING  THE  GILLEY  COILS 

Each  of  the  items  listed  and  illustrated  in  Figures  2,  3,  4,  5  and  7,  are  designed  for  use  with  the  Gilley  Coils  in 
performing  experiments  outlined  in  the  National  Loose-Leaf  Sheets  above  referred  to. 

92-116  SOFT  IRON  U-SHAPED  CORE,  Fig.  3,  for  study  of  bipolar  electro-magnets .  Each  $0.20 

92-117  SOFT  IRON  ARMATURE,  Fig.  2,  for  use  with  the  above  core  in  the  study  of  electro-magnets,  Each  .10 

92-120  SOFT  IRON  CORE,  Fig.  5,  single,  for  the  study  of  electro-magnets . .  Each  .10 

92-122  PAIR  OF  HALF-ROUND  CORE  PIECES,  Fig.  4,  for  mapping  the  lines  of  force  in  an  electro-magnet. 

Per  Pair  .15 

92-125  PAIR  OF  SLOTTED  CARDBOARDS,  Fig.  7,  for  mapping  lines  of  force.  . .  Per  Pair  .08 

Figures  8  and  9  in  the  illustration  show  how  the  above  apparatus  is  used  in  the  study  of  the  Simple  Transformer, 
Induced  Currents  and  Electro-Magnet. 

92-130  COMPLETE  GILLEY  INDUCTION  OUTFIT,  supplied  in  box,  with  direction  sheets .  $2.00 

92-136  ELECTROMAGNETIC  COILS, — a  set  of  three  coils  varying 
in  number  of  turns  and  character  of  core,  as  called  for  in 
Brownlee  &  Fuller’s  “Laboratory  Exercises,”  Exp.  82  .  .  1.60 

92-136  - ,  a  set  of  two  coils  after  Millikan,  Gale  and  Bishop,  Exp.  30 

Per  Set  1.10 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


33i 


Nos.  92-160  to  92-162 

92-160  INSTITUTE  IRON  CLAD  MAGNET,  Commercial  Form,  300  lbs.  capacity. 

In  the  design  of  this  magnet  careful  study  has  been  made  of  commercial  types  in  use.  The  defects 
of  previously  designed  laboratory  instruments  have  been  corrected,  with  the  idea  of  giving  the 
maximum  efficiency  per  pound  of  weight.  We  believe  this  to  be  the  only  laboratory  lifting  mag¬ 
net  on  the  market  in  which  the  cross  section  area  of  the  shell  is  equal  to  that  of  the  core  which,  of 
course,  is  necessary  in  order  to  secure  the  highest  efficiency  per  pound.  The  success  which  we 
have  attained  may  be  roughly  indicated  from  the  fact  that  on  one  cell  of  dry  battery,  this  mag¬ 
net  will  lift  approximately  thirty  times  its  own  weight.  ”  { 

In  actual  use,  we  recommend  a  voltage  of  from  4  to  6  volts,  the  latter  emf.,  of  course,  giving  the 
best  results. 

Size,  4  X  1  Yi  inches,  weight  with  armature,  5  pounds,  resistance,  1/3  ohm.  T . $4.60 

92-162  INSTITUTE  IRON  CLAD  MAGNET,  same  as  above,  but  smaller  in  size .  2.26 


No.  92-160 


No.  92-176 


No.  92-186 


92-160  SIX-INCH  DEMONSTRATION  ELECTRO-MAGNET.  This  instrument  is  intended  for  use  on 
a  battery  circuit  and  illustrates  in  a  most  striking  manner  the  great  magnetic  pull  obtained  from 
a  U-shaped  core. 

The  two  windings  of  this  magnet  can  be  connected  either  in  multiple  or  in  series.  Requires  five 


or  ten  volts,  depending  upon  method  of  connecting  coils. 

Core  (6  X  ^  inches)  is  of  special  grade  of  soft  iron .  2.36 

92-166  FOUR  AND  ONE-HALF  INCH  HELIX  ELECTRO-MAGNET.  New  York  State  form .  1.36 


92-176  HELIX  AND  SEPARABLE  MAGNETIC  CIRCUIT  (HELIX  AND  RING),  for  demonstrating  mag¬ 
netization  by  current. 

This  apparatus  consists  of  two  symmetrical  U-shaped  soft  iron  rods  each  with  a  handle.  A  detach¬ 
able  form-wound  helix  is  fastened  to  one  branch  of  one  of  these  U-shaped  pieces  so  that  when  the 
ends  of  the  U’s  are  placed  together  to  form  a  closed  magnetic  circuit  half  of  the  helix  will  cover 
one  of  the  branches  of  one  of  the  U’s  and  half  of  the  corresponding  branch  of  the  other  U. 

Before  battery  is  connected  no  magnetism  is  noticeable,  but  as  soon  as  current  is  allowed  to  pass 
through  the  helix  considerable  force  is  needed  to  separate  the  U’s. 

Complete  as  illustrated  . .  2.90 

92-186  SOLENOID  MAGNET,  for  illustrating  the  principle  of  a  solenoid  magnet. 

This  apparatus  consists  of  a  glass  tube  closed  at  one  end  and  on  which  is  fastened  a  helix  of  wire.  If 
now  a  bar  of  soft  iron  is  placed  so  that  it  rests  on  the  closed  end  and  the  helix  is  connected  to  source 
of  current  supply,  the  “sucking”  effect  of  the  magnetic  force  is  immediately  demonstrated. 


Complete  as  illustrated  with  soft  iron  rod .  1.70 

92-187  HELIX  or  SOLENOID  with  MOVABLE  COIL.  Helix  A}4  inches  long  with  connectors .  .90 


1 


332 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


Upright  Position  Horizontal  Position 

No.  92-195 


92-195  .  IMPROVED  MOUNTED  ELECTRO-MAGNET,  useful  as  a  demonstration  electro- magnet;  also 
for  remagnetizing.  In  this  design  mounted  for  use  in  the  two  positions  above  illustrated  we  offer 
not  only  a  design  capable  of  electro-magnetic  study  but  also  one  inferior  to  none  in  appearance 
and  utility. 

This  apparatus  consists  of  two  6-inch  U-shaped  soft  iron  cores  to  the  branches  of  which  are  attached 
two  removable  helices.  This  combination  is  mounted  on  a  neatly  finished  support  designed  for 
use  of  the  electro-magnet  in  two  positions.  Binding  posts  are  provided  for  connections  to  battery. 
Actual  tests  give  the  sustaining  power  of  this  instrument  of  from  150  to  200  pounds. 

Electro-magnet  mounted  as  illustrated . 


No.  92-200 


92-200  ONE-HUNDRED-TEN-VOLT  LIFTING  MAGNET.  This 

,  magnet  more  nearly  conforms  to  the  conventional  type  with 

the  important  modification  that  it  is  designed  to  operate  on  a 
110-volt  direct  current  and  will  easily  sustain  a  load  of  300 
pounds  weight. 

As  will  be  noted  from  the  illustration,  the  magnet  is  so  mounted 
that  it  may  be  easily  used  in  the  form  shown  in  the  illustration 
or  reversed  so  that  the  poles  extend  vertically  upward  or  sup¬ 
ported  in  a  horizontal  position  with  the  poles  extending 
outward. 

This  magnet  will  be  found  of  particular  value  in  connection 
with  the  important  series  of  experiments  on  magnetic,  and 
diamagnetic  materials. 

Stops  are  provided  for  limiting  the  movement  of  the  armature 
in  order  to  avoid  breakage. 

Specifications,  — 

Net  weight  of  magnet,  without  support,  10  lbs. 

Height  of  the  frame,  25  inches. 

Diameter  of  core,  1  inch. 

Size  of  winding,  X  inches. 

Resistance,  220  ohms. 

Ampere  consumption,  0.5  amp. 

Voltage  recommended,  110  volts. 

Lifting  power.  300  pounds, . 


i 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


333 


PARAMAGNETIC  AND  DIAMAGNETIC 
STUDY  APPARATUS 


No.  92-220  (Fig.  1)  No.  92-220  (Fig.  2) 


No.  92—220  (Fig.  3) 


No.  92-220  (Fig.  4)  No.  92-220 


92-220  PARAMAGNETIC  AND  DIAMAGNETIC  STUDY  OUTFIT  for  use  with  Magnet  No.  92-200  for 

general  electromagnetic  study,  but  especially  designed  to  facilitate  the  demonstration  of  para¬ 
magnetism  and  diamagnetism. 

The  outfit  consists  of  special  pole  pieces  for  attachment  to  the  pole  faces  of  Magnet  No.  92-200, 
and  the  following  additional  accessories. 

1.  Mounted  Copper  Disc  illustrating  retarding  and  stopping  of  rotation  due  to  the  current 

set  up  in  the  disc. 

2.  Mounted  Copper  Cylinder  illustrating  the  heating  effects  in  a  magnetic  field,  demon¬ 

strated  by  the  boiling  of  ether  placed  in  the  cylinder. 

3.  Mounted  Cubical  Vessel  and  Suspension  System  for  illustrating  Diamagnetism  and 

Paramagnetism,  including  ten  different  metal  rods,  —  lead,  silver,  bismuth,  nickel, 
copper,  iron,  zinc,  tin,  aluminum,  and  antimony,  each  with  a  small  hook  for  suspension. 

In  using  the  metals  on  suspension  support  the  hollow  cube  is  not  necessary,  as  this 
cube  is  used  to  show  the  magnetization  of  ferric  chloride  solution. 

4.  Insulation  Points  with  binding  screws  for  illustrating  diamagnetism  of  flames  and  the  de¬ 

flection  of  the  auriole  of  electric  discharges. 

Outfit  of  accessories  complete . $19.00 

92-226  PARAMAGNETIC  AND  DIAMAGNETIC  STUDY  APPARATUS.  This  outfit  is  complete  for  the 
study  of  paramagnetism  and  diamagnetism  and  for  general  electro-magnetic  study.  It  consists 
of  Magnet  No.  92-200  and  accessories  No.  92-220.  It  is  listed  complete  for  the  convenience  of 
teachers  who  do  not  already  have  Magnet  No.  92-200  and  who  desire  the  complete  equipment  .  36.00 


334 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ELECTRICAL  MEASURING  INSTRUMENTS 

GALVANOSCOPES 


No.  93-20 


93-12  GALVANOSCOPE,  after  Millikan  &  Gale’s 
“A  Laboratory  Course  in  Physics,”  pp.  80 
to  100. 

This  instrument  has  three  separate  cir¬ 
cuits,  each  with  two  binding  posts  for 
connections.  One  circuit  is  wound  with 
twenty-five  turns  of  No.  22  wire,  an¬ 
other  with  one  hundred  turns  of  fine 
wire,  and  another  with  a  single  turn  of 
coarse  wire.  Thus  it  may  be  seen  that 
the  sensibility  of  the  instrument  can  be 
changed  at  will  depending  upon  the  num¬ 
ber  of  turns  used  in  circuit  as  well  as  on 
the  position  of  the  compass  relative  to 
the  current  bearing  coil. 

Complete  as  illustrated,  but  without  com¬ 
pass  .  .  $1.20 

COMPASSES.  See  Section  81. 

ASTATIC  GALVANOMETERS 

93-20  ASTATIC  GALVANOMETER.  This  instrument  was  designed  according  to  the  requirements  of  the 
National  Physics  Course,  built  on  the  close-coil  type,  with  astatic  system  in  which  one  needle  moves 
between  the  coils  and  one  above.  Aluminum  dial  iyi  inches,  windings  of  No.  18  copper  wire,  re¬ 
sistance  approximately  one  ohm.  The  instrument  is  provided  with  three  leveling  screws  and  binding 
posts.  A  convenient  and  sensitive  instrument  where  low  voltage  only  is  to  be  used .  $3.60 

93-30  TROWBRIDGE  SENSITIVE 
GALVANOMETER.  This  in¬ 
strument  is  constructed  on  the 
close-coil  principle  in  which 
the  magnet  is  suspended  from 
a  light  aluminum  vane  hang¬ 
ing  in  front  of  the  coil.  Coils 
of  varying  resistances  may  be 
supplied  if  desired.  The  coil 
with  which  the  instrument  is 
furnished  is  intended  for 
Wheatstone  Bridge  work  and 
other  experiments  where  the 
voltage  is  exceedingly  low.  The 
end  of  the  aluminum  vane  pro¬ 
jects  into  a  metal  cup  under  the 
coil  which,  for  purposes  of  mak¬ 
ing  the  instrument  dead-beat, 
may  be  filled  with  glycerine,  if 
desired.  The  actuating  coil  is 
clamped  in  metal  clips  and  may 
be  easily  removed. 

This  instrument  has  the  advan¬ 
tage  over  the  conventional  form 
of  Astatic  Galvanometer  since 
all  the  parts  are  clearly  ex¬ 
posed.  The  instrument  is  more 
nearly  dead-beat  and  by  use  of 

an  outside  control  magnet,  for  which  the  instrument  is  well  adapted,  a  great  variation  in  sensibility 
is  obtained .  4.26 


No.  93-30 


No.  93-12 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


335 


TANGENT  GALVANOMETERS 


Nos.  93-40  to  93-50 

93-40  THE  SIX-INCH  TANGENT  GALVA¬ 
NOMETER  (or  GALVANOSCOPE),  a 

Tangent  Galvanometer  of  simple  con¬ 
struction,  coil  of  oxidized  brass  6  inches 
in  diameter,  arranged  with  binding- 
posts  which  connect  to  5,  10,  and  15 
turns  respectively "51  No.  18  wire.  Please 
note  that  all  connections  are  exposed  so 
that  the  student  can  very  easily  trace 
the  direction  of  the  current.  This  is  an 
important  feature  in  students’  work. 
The  compass  used  may  be  of  varying 
sizes,  brass  or  jewel  bearing,  any  size  of 
compass  being  held  in  the  exact  center  of 
the  coil  by  means  of  our  double  acting 
spring  clips.  With  the  short  needle  com¬ 
pass  the  instrument  naturally  conforms 
more  nearly  to  the  requirements  of  the 
Laws  of  Tangents. 


No.  93-60 


This  is  a  convenient  instrument  for  such  experiments  as  Tracing  the  Lines  of  Magnetic  Force,  rough 
experiments  in  Measurement  by  Substitution,  and  a  large  number  of  general  experiments  such  as 
ordinarily  given  in  the  first  year  science  courses.  The  educational  value  of  this  form  of  instru¬ 
ment  we  consider  far  greater  than  the  cheap  close-coil  instruments  sometimes  offered.  With  brass- 

capped  compass . 

93-44  STUDENTS’  SIX-INCH  TANGENT  GALVANOMETER,  with  agate-bearing  compass . 

93-60  STUDENTS’  SIX-INCH  TANGENT  GALVANOMETER,  with  large  compass  and  pointer  .... 


$2.20 

3.00 

3.65 


THE  HARCOURT  TWENTY-TWO  CENTIMETER  TANGENT 

GALVANOMETER 


This  Galvanometer  is  designed  for  High  School  use.  It  has  all  of  the  essentials  of  the  higher-priced  instruments. 
It  is  of  substantial  construction  but  without  unnecessary  finish. 

We  employ  an  aluminum  ring  22  centimeters  in  diameter  which,  with  a  2-centimeter  magnet,  enables  the  laws 
of  the  Tangent  Galvanometer  to  be  definitely  determined.  The  coil  is  6  millimeters  wide,  so  that  errors  resulting 
from  this  source  are  reduced  to  a  minimum.  Provided  with  leveling  screws  and  compass  box  11  centimeters  in  di¬ 
ameter,  mirror  dial  and  glass  dome.  This  compass  box  is  easily  removable  by  loosening  two  set  screws  shown  on 
the  cross  bar.  With  the  compass  box  removed  the  instrument  is  readily  made  use  of  in  a  variety  of  experiments  on 
induction.  The  instrument  is  provided  with  four  binding  posts  connecting  consecutively  to  5,  10,  and  15  turns 


of  wire. 

93-60  THE  HARCOURT  TWENTY-TWO  CENTIMETER  TANGENT  GALVANOMETER,  with  fiber  sus¬ 
pended  needle  and  long  aluminum  pointer  and  mirror  dial .  $7.16 

93-65  THE  HARCOURT  TWENTY-TWO  CENTIMETER  TANGENT  GALVANOMETER,  with  jewel- 

bearing  magnet  and  long  aluminum  pointer  in  place  of  the  fiber  suspension .  7.15 


336 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


TANGENT  GALVANOMETERS 


No.  93-75 


93-75  STANDARD  TANGENT  GALVANOMETER.  This  is  a  distinctly  higher  grade  instrument  than  the 
preceding.  All  parts  have  been  made  with  the  greatest  care.  As  will  be  noted  from  our  illustration 
it  is  provided  with  a  Thompson  adjustable  control  magnet  with  both  a  vertical  and  horizontal 
motion.  It  slides  on  a  post  in  a  carefully  adjustable  sleeve.  A  coil  13  millimeters  wide  is  mounted 
on  a  finished  brass  ring  20  centimeters  in  diameter.  This  ring  is  mounted  on  a  substantial  base  to 
the  binding  posts  of  which  are  carried  the  terminals  of  the  coil'. 

The  suspension  system  consists  of  a  needle  15  millimeters  long,  suspended  by  fiber  and  provided  with 
a  convenient  and  satisfactory  lift.  The  needle  is  protected  by  a  box  1234  centimeters  in  diameter, 
provided  with  silvered  engine-divided  dial. 

To  meet  the  conditions  of  the  greatest  variety  of  experiments  in  practical  laboratory  work  and  also 
for  determining  the  constant  in  a  tangent  galvanometer  the  windings  have  been  carefully  worked  out 
as  follows:  — 

3  turns  of  coarse  wire  connected  to  posts  1  and  2,  wound  clock-wise. 

12  turns  of  coarse  wire  connected  to  posts  2  and  3,  wound  counter  clock- wise,  giving  be¬ 
tween  posts  2  and  3,  nine  turns  of  coarse  wire  wound  counter  clock-wise. 

320  turns  of  fine  wire  connected  to  posts  1  and  4,  wound  clock-wise.  This  coil  is  especially 
designed  for  determining  the  constant  of  a  tangent  galvanometer. 

We  have  no  hesitancy  in  claiming  that  this  is  one  of  the  most  carefully  designed  and  scientifically 


proportioned  galvanometers  on  the  market . $33.00 

93-80  - ,  same  as  above,  but  mounted  on  polished  hardwood  base  in  place  of  the  tripod .  22.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


337 


D’ARSONVAL  GALVANOMETERS 

The  enormous  increase  in  the  use  of  electric  current  and  the  employment  of  iron  in  the  construction  of  build¬ 
ings  make  necessary  the  use  of  a  type  of  measuring  instrument  which  is  not  affected  by  outside  magnetic  influences. 
Of  the  different  types  devised  the  only  one  which  survives  by  its  general  fitness  is  the  Deprez-D’Arsonval,  usually 
called  the  D’Arsonval  Galvanometer,  but  which  was  first  used  by  Thompson  in  his  work  on  the  Atlantic  cable. 

So  free  is  this  instrument  from  magnetic  influences  that  it  can  be  used  close  to  large  dynamos  and  motors.  Owing 
to  the  method  of  suspension,  the  powerful  magnetic  moment  exerted  by  its  moving  coil,  and  the  great  restoring 
force  of  the  suspension,  it  is  singularly  free  from  the  effects  of  vibration  as  compared  with  the  older  types  of  instru¬ 
ments.  In  short,  a  well-designed  D’Arsonval  Galvanometer  is  almost  the  ideal  instrument  for  indicating  and  meas¬ 
uring  electric  currents  in  laboratories  devoted  to  either  educational  work  or  to  technical  research. 

Development  in  the  D’Arsonval  Galvanometer  construction  has  made  such  rapid  progress  that  exceedingly 
sensitive  instruments,  if  correctly  designed,  are  now  practical  for  placing  in  the  students’  hands. 

As  will  be  noted  from  the  illustrations  on  the  following  pages,  we  use  the  D’Arsonval  principle  on  instruments 
designed  both  for  lecture  table  demonstration  and  for  students’  individual  laboratory  work. 

MEASURE  OF  SENSIBILITY.  In  the  rating  of  all  of  our  galvanometers  we  use  the  “megohm  standard,” 
recognized  by  the  best  European  manufacturers  as  the  one  which  conveys  most  intelligibly  the  information  the  user 
should  have  at  hand. 

MAGNET  SYSTEM.  Wherever  practical  we  use  the  laminated  magnet  for  the  reason  that  it  gives  not  only 
greater  magnetic  pull  per  unit  area,  but  more  particularly  because  of  its  ability  to  hold  its  magnetic  strength  with 
less  loss  from  rough  usage.  It  will  also  be  noted  that  we  use  the  closed  circuit  magnet  because  of  its  well-recognized 
quality  of  greater  strength  and  permanency.  This  form  of  magnet  has  not  heretofore  been  largely  used  because  of 
the  greater  expense  involved  in  properly  magnetizing  it.  The  ampere  turn  method  which  we  use  has  been  recog¬ 
nized  as  the  only  reliable  one  for  magnetizing  a  magnet  designed  for  use  in  galvanometer  work.  The  expense,  how¬ 
ever,  involved  in  this  method,  particularly  in  the  closed  circuit  type  of  magnet,  is  such  as  heretofore  to  have  dis¬ 
couraged  many  manufacturers  from  using  this  type  of  magnet. 

SUSPENSION  SYSTEM.  We  have  designed  a  form  of  suspension  system  which  is  used  in  practically  all  of 
our  D’Arsonval  types  of  instruments,  both  lecture  table  and  students’  type.  In  this  form  the  entire  suspension 
system  can  very  easily  be  removed  from  the  magnets,  placed  on  the  table  in  an  easily  accessible  position  for  the  ready 
interchange  of  suspension.  This  will  be  found  of  convenience  at  times,  notwithstanding  the  fact  that  the  liability 
of  breakage  of  the  suspension  has  been  greatly  reduced.  We  supply  suspension  ribbons  and  coils  with  connecting 
strips  which  can  be  attached  almost  instantly  without  the  aid  of  either  a  screw  driver  or  soldering  copper. 

COILS.  All  coils,  unless  otherwise  specified,  are  of  the  dead-beat  form,  but  for  Capacity  and  Induction  work 
we  supply,  when  ordered,  coils  especially  adapted  to  this  work  for  either  type  of  instrument. 

METHOD  OF  READING.  The  method  of  reading  employed  is  such  in  every  case  as  is  best  adapted  to  the 
particular  type  of  instrument  and  the  use  to  which  it  is  to  be  put.  On  the  various  types  we  use  the  several  different 
systems  as  here  specified: 

A  POINTER,  reading  on  either  the  vertical  or  horizontal  scale. 

MIRROR  READING,  employing  the  back  target  fiducial  mark,  making  it  possible  to  use  a  front  opening  wide 
enough  for  both  eyes  to  be  used  in  their  normal  position  without  errors  of  parallax. 

THE  MIRROR  METHOD  with  the  small  peek  hole  front  target,  designed  more  particularly  for  advanced 

students. 

TELESCOPE  READING.  All  of  our  instruments,  except  the  inexpensive  students’  types  Nos.  93-198  and 
93-200,  are  supplied  with  mirrors.  The  regular  reading  device  may  be  very  easily  removed  and  the  instrument 
used  as  a  telescope  reading  instrument. 

THE  TELESCOPE  MOUNTING  and  BRACKET,  illustrated  under  No.  93-246,  is  designed  of  such  size  as  to 
take  any  of  our  standard  types  of  instruments. 


338 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


LECTURE  TABLE  GALVANOMETERS 

No.  93-130 

UNIVERSAL  LECTURE  TABLE  GALVANOMETER 

EIGHT  INSTRUMENTS  IN  ONE 


Patent  Pending 


Designed  for  a  practical  and  reliable  Lecture  Table  instrument  covering  a  wide  range  and  giving  one  division 
deflection  on  .002  of  a  volt. 

The  movement  is  of  the  commercial  D’Arsonval  type  but  slightly  modified;  the  moving  coil  adjusted  for  one 
ohm  resistance,  making  it  possible  to  supply  at  any  time  detachable  and  interchangeable  shunts  or  resistances  of 
any  desired  range. 


EIGHT  INSTRUMENTS  IN  ONE 

The  following  eight  instruments  are  therefore  available  in  this  one  outfit: 

1.  A  Galvanometer  in  which  one  space  deflection  means  .002  of  an  ampere  or  .002  of  a  volt. 

2.  A  Millivoltmeter  in  which  the  entire  scale  deflection  means  25  millivolts  in  yi  millivolt  divisions. 

3.  A  Milliamperemeter  in  which  the  entire  scale  deflection  means  25  milliamperes  in  yi  milliampere 

divisions. 

4.  A  Voltmeter  range  of  0-5  volts  in  1/10  volt  divisions. 

5.  A  Voltmeter  range  of  0-25  volts  in  yi  volt  divisions. 

6.  A  Voltmeter  range  of  0-125  volts  in  2 volt  divisions. 

7.  An  Amperemeter  range  of  0-5  amperes  in  1/10  ampere  divisions. 

8.  An  Amperemeter  range  of  0-25  amperes  in  yi  ampere  divisions. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


339 


DIAL.  The  dial  is  twelve  inches  long  with  wide  and  clearly  indicated  divisions.  Note  below  the  reproduction 
of  the  scale  about  1/5  size.  It  may  easily  be  read  from  any  part  of  the  lecture  room. 

FOR  THE  INSTRUCTOR’S  CONVENIENCE  the  back  of  the  dial  carries  a  scale  with  full  and  explicit  direc¬ 
tions  for  connecting.  On  the  base  is  a  protecting  switch  to  avoid  accidentally  burning  out  the  coil  by  a  mis-connection. 


A  NEW  METHOD  OF  CONNECTING  SHUNTS,  which  automatically  insures  the  same  contact  pressure  on 
both  the  shunt  and  coil  circuit.  This  eliminates  all  liability  of  contact  error  in  the  shunt  system. 

UNIVERSAL  FEATURES.  We  have  produced  an  instrument  in  which  both  the  educational  and  commercial 
features  have  been  carefully  considered  and  economically  solved. 

ACCURACY.  The  calibration  is  done  in  connection  with  the  best  standard  commercial  instruments.  All  parts 
are  carefully  constructed.  The  magnets  are  aged  by  the  standard  aging  method.  The  jewel  bearings  are  best 
quality  sapphire.  In  short,  we  believe  this  instrument  to  be  the  best  electrically,  mechanically,  and  educationally, 
that  has  ever  been  offered. 


93-130  UNIVERSAL  LECTURE  TABLE  GALVANOMETER,  complete  with  full  set  of  Shunts  and  Resist¬ 
ances  giving  ranges  previously  listed . $35.00 

EXTRA  SHUNTS  AND  RESISTANCES.  Should  an  instrument  of  any  other  range  than  that 
already  provided  for  be  desired,  the  proper  shunts  and  resistances  will  be  furnished  on  special 
order  at  the  net  price  each  of .  2.50 


L.  E.  KNOTT  APPARATUS  COMPANY 
Harcourt  Street, 

Boston,  Mass. 

Gentlemen,  —  Let  me  add  that  your  Galvanometer  has  been  a  most  thoroughly  satisfactory  instrument  and  wonderfully  sensitive. 

Very  sincerely  yours, 

(Signed)  Harold  B.  Reed, 

February  21,  1912.  Instructor  in  Physics, 

East  High  School, 

Cleveland,  Ohio. 

Gentlemen,  —  Your  Lecture  Table  Galvanometer  has  been  a  great  help  in  teaching  the  subject  of  current  electricity  to  mixed  classes. 
The  fact  that  all  connections  and  moving  parts  are  plainly  in  view,  and  the  scale  large  and  open,  and  the  ranges  large  make  it  an  ideal  edu¬ 
cational  instrument. 

The  use  of  the  ammeter  shunts  and  of  the  switch  shunt  and  their  effects  on  the  deflection  of  the  needle,  tend  to  clear  up  the  subject  of 
divided  circuits. 

I  have  it  before  my  classes  during  our  study  of  current  electricity  and  use  it  constantly.  It  is  a  usable  and  extremely  satisfactory  in¬ 
strument  and  one  that  should  be  in  every  Physics  lecture  room. 

Very  truly, 

March  15,  1912.  (Signed)  Ernest  R.  Smith, 

North  High  School, 

Syracuse,  N.  Y. 

Gentlemen, _ The  Lecture  Table  Galvanometer  has  been  received  and  in  good  condition.  Needless  to  say  I  am  much  pleased  with 

it  and  will  make  excellent  use  of  it.  In  fact,  it  is  just  about  the  device  I  have  been  looking  for  and  it  is  probable  that  I  shall  order  a  second 
unit  of  this  kind  for  our  laboratory,  next  year. 

Very  truly  yours, 

March  28,  1912.  (Signed)  William  H.  Browne,  Jr., 

N.  C.  Coll,  of  Agriculture  &  Mechanic  Arts, 
West  Raleigh,  N.  C. 


340 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  i 


No.  93-146 


93-146  LECTURE  TABLE  GALVANOMETER.  As  will  be  noted  from  the  cut,  this  instrument  is  mounted 
vertically,  of  sufficient  height  for  lecture  table  use.  The  scale  is  large  and  open  so  as  to  be  seen 
across  the  lecture  room,  the  pointer  of  aluminum,  the  bearings  jewel,  the  moving  system  a  \y£- 
inch  magnet.  The  windings  are  in  three  sections,  —  coarse,  medium,  and  fine  wire  of  varying  re¬ 
sistances  and  varying  ranges. 

This  is  not  designed  for  an  instrument  of  high  sensibility,  but  rather  to  cover  the  widest  range  feasi¬ 
ble  to  attain  in  an  inexpensive  lecture  table  instrument. 

It  will  be  found  well  adapted  for  such  experiments  as  polarization,  the  study  of  the  relative  strength 
of  cells  either  in  groups  or  in  multiple,  experiments  on  induction  taken  in  the  larger  way,  and  many 
other  experiments  which  will  suggest  themselves  as  adapted  to  this  range  of  instrument  .... 


No.  93-166 


93-166  THE  LAMPRA  PROJECTION  GALVANOMETER.  This  galvanometer  is  of  the  same  genera 
type  as  used  in  France  and  Germany  in  the  early  days  of  the  pivotal  bearing  D’Arsonval.  It  has, 
however,  been  greatly  improved  by  taking  advantage  of  more  recent  developments  in  galvanometer 
construction. 

As  will  be  noted  from  the  illustration,  it  is  especially  adapted  for  projection  work,  the  scale  chamber 
being  of  the  regulation  slide  holder  size  with  glass  both  sides  of  the  indicator.  The  galvanometer 
movement  is  encased  in  a  compact  box  mounted  so  as  to  give  adequate  adjustment  for  any  form 
of  Projection  Lantern,  the  indicator  moving  over  an  arbitrary  scale.  The  entire  instrument, 
including  the  indicator  chamber,  is  sealed  for  proper  protection  against  dust  and  air  currents.  A 
most  effective  and  convenient  demonstration  instrument  for  lantern  work . 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


34i 


No.  93-175 

THE  IMPROVED  LAMINATED  MAGNET 

LECTURE  TABLE  GALVANOMETER 

30  MEGOHM  SENSIBILITY 


MAGNETS.  As  the  illustration  shows,  this  instrument  is  made  up 
of  four  horizontal  magnets.  Because  of  the  form  of  the  magnet,  and 
the  fact  that  the  whole  system  is  laminated,  we  are  able  to  produce  a 
magnetic  pole  of  a  strength  at  least  five  times  that  used  in  any  other 
Lecture  Table  Galvanometer  on  the  market. 

COIL.  We  have  employed  the  cylindrical,  close-wound  coil  recog¬ 
nized  by  instrument  makers  the  world  over  as  being  the  only  form  in 
which  the  deflections  bear  the  proper  relation  to  the  current  strength. 
The  value  of  such  a  coil  in  a  Lecture  Table  Galvanometer  is  of  especial 
consideration,  as  both  the  lecturer  and  the  students  are  able  to  recognize, 
from  the  amount  of  deflection,  the  relative  amperage  passing  through  the 
coil. 

SCALE.  Our  instrument  is  designed  or  a  60  degree  deflection 
either  side  of  zero,  making  a  total  of  120  degrees.  Note,  also,  that  the 
instrument  is  provided  with  four  scales  and  double  pointer.  A  vertical 
scale  on  both  sides  of  the  instrument  with  coarse  divisions,  is  especially 
intended  for  students’  readings.  A  horizontal  finely  divided  scale  on 
top  of  the  magnet  on  both  front  and  back  is  of  value  to  the  instructor 
or  students  desiring  to  make  closer  readings  than  can  easily  be  made  on 
the  coarse  scale  intended  for  wide  range  work. 


NON— PARALLAX  READING  DEVICE.  As  will  be  noted  from  the  illustration,  the  vertical  scale  is 
offset  in  such  a  way  that  the  large  triangular  pointer  does  not  over-lap  the  scale,  but  is  in  the  same  line  with 
it,  making  it  possible  to  use  the  so-called  “straight  line  method  of  reading,”  which  avoids  all  errors  of 

parallax. 


ZERO  ADJUSTMENT.  A  convenient  and  most  desirable  method  of  adjusting  the  pointer  to  zero 
has  been  worked  out,  using  the  chain  and  sprocket,  one  sprocket  being  mounted  on  the  upper  end  of  the  ver¬ 
tical  shaft  passing  down  the  inside  of  the  supporting  post.  On  the  other  end  of  this  shaft  is  a  milled-edge 
disc  projecting  slightly  beyond  the  base  to  the  left  in  a  most  convenient  and  accessible  position.  With  this 
arrangement  the  needle  is  quickly  and  easily  adjusted  to  zero  without  raising  the  glass  dome. 

COIL  LIFT.  For  safety  in  shipping  and  in  handling,  the  coil  is  easily  raised  from  the  suspension  ribbon 
by  a  knob  conveniently  located  on  the  base,  on  the  right  of  the  instrument. 


METHOD  OF  ATTACHING  SUSPENSION  RIBBONS.  In  D’Arsonval  Galvanometers,  using  the 
steel  or  phosphor-bronze  ribbon,  there  is  some  danger  of  breaking  the  suspension,  owing  to  carelessness  in 
handling  the  instrument  before  the  coil  is  raised  to  shipping  position.  As  will  be  noted  in  the  diagram,  the 
upper  portion  of  the  coil  terminates  in  a  horizontal,  close-wound  spiral  between  the  turns  of  which  the  suspen¬ 
sion  plate  is  inserted.  Should,  therefore,  breakage  accidentally  occur,  we  can  furnish  a  new  ribbon  with  the 
suspension  plates  attached,  which  the  customer  can  insert  quickly  and  easily  without  the  use  of  a  screw  driver 
or  soldering  copper.  This  feature  makes  this  lecture  table  instrument,  as  well  as  our  complete  line  of  D’Arson¬ 
val  Galvanometers,  practical  for  use  by  the  most  inexperienced. 

SENSIBILITY.  We  have  thought  it  best  to  adjust  this  galvanometer  to  a  considerably  higher  sensibility 
than  is  ordinarily  furnished  for  lecture  table  work,  as  it  permits  an  entirely  new  field  of  experiments  not  possi¬ 
ble  with  the  instruments  usually  supplied.  In  case,  however,  it  is  desired  to  reduce  the  sensibility,  this  can 
be  very  easily  done  by  inserting  a  coil  in  the  form  of  a  shunt.  Special  coils  for  this  work  will  be  supplied  if 
desired.  While  it  is  perfectly  feasible,  with  our  methods  of  construction,  to  put  out  an  instrument  of  very  much 
higher  sensibility,  it  has  seemed  to  us  that  30  megohms  would  meet  the  greatest  variety  of  conditions.  This 
instrument,  therefore,  will  be  adjusted  to  approximately  this  sensibility. 

THE  IMPROVED  LAMINATED  MAGNET  LECTURE  TABLE  GALVANOMETER,  complete  as  above 
illustrated . $16.00 


342 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


LABORATORY  D’ ARSON VAL 
GALVANOMETERS 


No.  93-195 


93-195 HORIZONTAL  GALVANOMETER,  D’Arsonval  move¬ 
ment,  jewel  bearing,  0  center.  This  is  a  commercial 
type  'of  instrument  in  horizontal  or  laboratory  form. 
The  range  is  such  as  to  make  it  of  the  greatest  value  in 
general  laboratory  practice.  Quick  action,  quick  read¬ 
ing,  adapted  to  a  wide  range  of  experiments,  such  as  In¬ 
duction,  Polarization  of  Cells,  Measurements  of  the 
Wheatstone  Bridge,  where  an  accuracy  equal  to  K 
millimeter  on  the  bridge  is  considered  sufficient. 

Owing  to  the  form  of  the  pole  pieces  the  scale  is  propor¬ 
tional  to  the  amount  of  current  going  through,  thus 
giving  the  instrument  a  range  of  usefulness  far  greater 
than  its  sensibility  would  indicate. 

Jewel  bearing,  mahogany  base,  aluminum  case.  A  sub¬ 
stantial,  convenient,  well-constructed  instrument  of 
the  D’Arsonval  type . 


No.  93-200 

Patent  Pending 


93-198  HARCOURT  IMPROVED  D’ARSONVAL  GALVANOMETER  similar  to  No.  93-200,  but  single 

magnet  type.  Designed  particularly  for  “Laboratory  Physics”  by  Millikan,  Gale  and  Bishop. 

93-200  THE  TRIPLE  LAMINATED  MAGNET  HIGH  SCHOOL  GALVANOMETER.  The  simplicity  of 
construction  and  ease  of  use  in  a  students’  laboratory  galvanometer  are  quite  as  essential  as  sensi¬ 
bility.  In  the  instrument  above  illustrated,  simplicity  and  ease  of  operation  are  obtained  to  an 
extent  which  a  few  years  ago  was  considered  impossible.  The  simplicity  of  this  design  will  appeal 
to  the  practical  laboratory  instructor.  Its  sensibility  is  well  within  the  range  which  such  instru¬ 
ments  are  designed  to  meet. 

Features.  The  triple  laminated  magnet  gives  greater  magnetic  pull,  enabling  heavier  ribbon  sus¬ 
pensions  to  be  used,  thus  decreasing  the  liability  of  breakage. 

As  will  be  noted,  the  coil  is  of  the  close-wound  type,  the  same  as  employed  in  our  Galvanometer 
No.  93-210,  a  form  of  peculiar  value  in  an  instrument  designed  for  individual  laboratory  work,  as 
the  student  should  be  able  to  determine  from  the  amount  of  deflection,  the  approximate  voltage 
and  amperage  to  which  the  instrument  is  subjected. 

The  entire  suspension  system  may  be  removed  by  loosening  a  single  screw.  Should  the  suspension 
ribbon  be  accidentally  broken,  a  new  one  may  be  readily  inserted  in  a  few  seconds  by  the  student. 
No  soldering  copper  or  screw  driver  is  required. 

The  zero  adjustment  is  readily  made  by  turning  the  metal  button  at  the  top  of  the  suspension  post. 

A  most  efficient  coil  lift  is  provided  which  raises  the  coil  from  its  suspension  and  clamps  it  rigidly  in 
position,  ready  for  rough  handling  and  for  shipping. 

For  convenience  the  readings  are  taken  by  a  pointer  moving  over  a  3 J^-inch  horizontal  dial  grad¬ 
uated  in  degrees. 

Sensibility.  The  rating,  according  to  the  standard  method,  is  about  thirty  megohms,  although  the 
construction  of  the  instrument  is  such  as  to  permit  of  a  higher  sensibility  should  it  be  deemed 
desirable  to  use  such  in  the  work  for  which  this  instrument  was  designed. 

Complete . 


$7.50 


$2.75 


4.80 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


343 


93-210  THE  LAMINATED  VERTICAL  MAGNET  GAL¬ 
VANOMETER  (The  One  Ohm  per  Megohm). 

A  laboratory  galvanometer  designed  with 
special  reference  to  the  needs  of  the  individual 
student  will  be  fully  appreciated.  It  has  been 
our  purpose  to  construct  an  instrument  which 
can  be  easily  set  up,  adjusted  and  kept  in  ad¬ 
justment  and  one  in  which  all  working  parts 
are  constantly  in  view. 

The  unit  suspension  system  which  has  been  worked 
out  according  to  the  lines  noted  in  the  detailed 
illustration  carries  the  coil,  upper  and  lower  sus¬ 
pension,  zero  adjustment  and  lift,  all  constitut¬ 
ing  a  single  unit  attached  to  the  back  brass  plate. 

In  setting  up  the  instrument  this  plate  is  held 
rigidly  between  the  magnets  by  means  of  four 
screws,  removing  the  thumb  nuts  from  which  re¬ 
moves  the  entire  system  for  inserting  Ballistic 
Coils,  coils  of  high  or  low  resistance,  or  for  re¬ 
placing  broken  suspensions. 

Our  suspensions  are  supplied  with  metal  terminals 

which  are  easily  slipped  between  the  convolutions  of  the  phosphor-bronze  spiral  with  which 
the  coil  is  supplied,  insuring  a  perfect  electrical  and  mechanical  contact.  The  lower  suspension, 
which  has  heretofore  been  replaceable  only  by  a  person  with  much  experience,  is  now  even  more 
easily  handled  than  the  upper  suspension,  as  each  spiral  is  sent  out  contained  in  a  sealed  glass  tube, 
the  terminals  passing  through  the  upper  and  lower  ends  of  the  tube.  After  the  coil  is  set  in  place 
and  the  adjustment  made,  the  seal  is  cut  away;  the  galvanometer  is  then  ready  to  use,  all  without 
touching  the  spiral  with  either  tools  or  fingers. 

We  have  used  on  this  instrument  the  modified  form  of  the  reading  device  used  on  our  original  stu¬ 
dents’  D’Arsonval  Galvanometer  with  the  very  important  modification  that  the  user  now  looks 
in  an  inclined  position,  permitting  the  galvanometer  to  be  used  on  the  surface  of  the  table  and 
avoiding  the  necessity  of  either  getting  down  to  the  level  of  the  mirror,  or  of  raising  the  galva¬ 
nometer  to  the  height  of  the  eye. 

The  sensibility  of  this  instrument  is  equal  to  all  requirements  for  laboratory  work.  As  ordinarily 
sent  out,  these  instruments  are  adjusted  for  70  megohms  sensibility.  A  higher  sensibility  than  this 
is  readily  obtainable  if  there  be  adequate  demand  for  it. 

POINTS  OF  ADVANTAGE 

The  resistance  is  approximately  the  same  as  the  sensibility  in  megohms,  —  one  ohm  per 
megohm.  \ 

The  unit  suspension  system. 

The  visibility  of  all  parts. 

The  readiness  of  assembling  and  adjustment. 

The  ease  of  replacing  broken  suspensions. 

The  magnetic  strength  and  permeability  due  to  the  laminated  magnet. 

A  method  of  reading  which  is  practical  in  the  hands  of  the  most  inexperienced. 

The  zero  adjustment  which  is  effective  and  easily  handled. 

The  coil  lift,  conveniently  located  and  instantly  operated  by  a  single  movement. 

A  sensibility  of  70  megohms,  being  substantially  four  times  that  obtained  in  any  other  stu- 
ents’  type  of  instrument. 

Unusual  low  resistance,  —  about  70  ohms . 

93-215  BALLISTIC  COIL.  The  above  instrument,  No.  93-210,  is  especially  adapted  for  the  use  of  Ballistic 
Coils  in  Capacity  and  Self-Induction  experiments.  The  most  convenient  method  of  inserting  the 
coils  is  to  obtain  a  unit  suspension  system  with  the  Ballistic  Coil  attached.  The  new  system  can 
then  be  inserted  very  easily. 

Unit  Ballistic  System  complete  ready  for  attaching . 


$6.45 


6.00 


344 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


METHOD  OF  READING.  The  method 
of  reading  is  effective,  overcoming  er¬ 
rors  of  parallax.  The  reading  scale 
may  be  easily  removed  by  loosening 
two  thumb  nuts.  The  instrument  is 
then  well  adapted  for  telescope  reading. 
When  it  is  desired  to  use  this  as  a  wall 
form  instrument  for  telescope  reading, 
we  recommend  telescope,  scale,  mount¬ 
ing  and  bracket.  (See  Index) . 

No.  93-220 

93-230  SIX  HUNDRED  MEGOHM  SELF-LEVELING  D’ARSONVAL  GALVANOMETER,  either  wall  or 
table  type  (see  illustration  next  page).  A  galvanometer  for  advanced  laboratory  work  which  is 
both  self-centering  and  self-leveling,  used  either  as  a  wall  or  table  instrument.  The  entire  in¬ 
strument  is  hung  from  universal  gimbals  so  that  both  magnet  and  coil  are  always  in  correct  re¬ 
lation. 


93-220  TWO  HUNDRED  MEGOHM  D’ARSON¬ 
VAL  GALVANOMETER,  an  instrument 
of  high  sensibility  for  use  with  either 
scale  or  telescope  reading. 

The  method  of  suspending  the  coil  system 
will  be  found  of  the  greatest  practical 
value;  the  entire  system  may  be  taken 
out  by  loosening  the  set  screws  and  re¬ 
moving  the  back  plate,  as  noted  in  the 
illustration.  Broken  suspensions  may 
be  very  easily  replaced. 

SENSIBILITY.  These  instruments  are 
approximately  200  megohms  sensibility, 
of  quick  movement  and  practically 
dead-beat. 


As  a  wall  instrument.  This  has  a  great  advantage  in  overcoming  the  difficulties  usually  encountered 
in  fastening  an  instrument  to  the  wall  and  securing  the  proper  level. 

As  a  table  instrument.  The  advantages  are  even  more  pronounced,  as  the  self-centering  permits 
absolute  freedom  of  movement  from  one  portion  of  the  table  to  another,  with  assurance  that  the 
instrument  will  instantly  assume  a  level  and  be  ready  for  use. 

Telescope  mounting  and  bracket.  The  supporting  stand  for  the  galvanometer  was  designed  to  fit 
our  Universal  Galvanometer  and  Telescope  Support  No.  93-240.  When  the  two  instruments 
are  used  together,  a  most  convenient  and  effective  galvanometer  outfit  is  obtained. 

Reading  Device.  A  two-color  scale  mounted  in  a  sliding  socket  for  adjusting  to  zero,  telescope  on  an 
adjustable  arm  with  leveling  screws  which  may  be  removed  when  not  in  use. 

The  Achromatic  Telescope,  especially  designed  for  galvanometer  work. 

Magnet  System.  By  our  method  of  magnet  construction  we  secure  far  greater  strength  and  per¬ 
manency  than  are  obtained  in  any  other  galvanometer  magnet  on  the  market.  The  concentration 
of  the  lines  of  force  to  meet  the  size  and  form  of  the  coil  has  been  the  subject  of  much  careful 

study. 

» 


$16.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


345 


Coil  System.  A  removable  coil  system  insures  easy  access  to  all 
delicate  parts  and  the  ready  replacement  of  broken  suspensions. 

Extra  coil  systems  designed  for  special  work  supplied  on  request. 

Sensibility.  As  ordinarily  furnished,  the  instrument  is  supplied 
with  a  coil  of  400  ohms  resistance,  giving  a  sensibility  of  over  600 
megohms,  the  range  which  has  met  with  the  greatest  favor. 

The  Mirror  is  optically  plane,  yi  x  %  inch. 

Suspensions.  By  carefully  adjusting  the  weight  of  the  coil  to  the 
size  of  the  phosphor-bronze  suspension,  we  have  practically  elimi¬ 
nated  the  zero  set,  but  for  those  who  prefer  the  steel  suspension 
this  will  be  furnished. 

Complete  as  illustrated . $32.00 


No.  93-230 

93-232  EXTRA  COILS,  either  Ballistic,  low,  or  high  resistance  as  specified,  are  furnished  for  use  with  the 

above  instrument . Each  7.50 

93-235  RADIO  MICROMETER.  In  scientific  work  the  Radio  Microm¬ 
eter  has  long  been  recognized  as  not  only  the  most  sensitive, 
but  the  most  reliable  heat  indicator  produced.  In  putting  this 
sensitive  instrument  into  practical  form,  we  have  used  the  funda¬ 
mental  parts  of  the  D’Arsonval  Galvanometer,  —  magnet  sys¬ 
tem,  mirror  and  reading  device,  but  with  the  moving  coil  replaced 
by  the  most  sensitive  thermo-electric  couple  which  it  is  possible  to 
construct,  with  a  suspension  to  hold  the  couple  in  position,  and 
designed  to  introduce  the  least  possible  amount  of  restraining 
influence. 

Sensibility.  In  radio-micrometer  work,  the  candle  flame  at  definite 
distance  has  been  found  a  convenient  standard.  It  is  possible 
with  our  instrument  to  detect  an  amount  of  heat  equal  to  that 
received  from  a  candle  flame  at  a  distance  of  50  feet,  giving  clearly 
indicated  readings  on  the  dial. 

Method  of  Reading.  With  many  radio-micrometers  previously 
constructed,  the  readings  must  be  taken  with  the  telescope  method 
owing  to  the  fact  that  the  deflections  caused  by  the  heat  of  the  No.  93-235 

body  make  it  necessary  for  the  observer  to  remain  at  a  consider¬ 
able  distance.  Much  of  this  difficulty  has  been  overcome  by 
our  method  of  introducing  heat  to  the  thermo  system.  The 
directing  horn  is  mounted  on  a  movable  ring  so  that  the  heat  may 
be  taken  either  from  one  side  of  the  instrument  or  the  other,  but 
not  from  the  front  where  the  observer  would  naturally  stand. 

The  moving  system  being  provided  with  a  mirror  and  the  close-reading  scales  easily  removable,  the 
telescope  method  of  reading  will  be  found  in  some  cases  more  satisfactory. 

Complete  instructions  for  use  will  be  furnished  with  each  instrument. 

Complete  as  illustrated  . $16.00 


346 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


UNIVERSAL  GALVANOMETER  WALL- 
BRACKET  AND  TELESCOPE  SCALE 

ADAPTED  TO  ANY  TYPE  OF  INSTRUMENT 


No.  93-246 


93-240  GALVANOMETER  WALL-BRACKET  and  TELESCOPE  SCALE.  Heretofore  sensitive  galva¬ 
nometers  have  been  attached  rigidly  to  the  wall,  it  being  necessary  to  level  them  with  the  greatest 
care.  When  once  attached  and  adjusted,  the  galvanometer  is  allowed  to  remain  on  the  wall 
permanently. 

Our  rigid  wall  shelf  for  galvanometer  work,  carrying  the  telescope  arm  and  scale,  gives  a  method 
of  using  galvanometers  much  more  satisfactory  than  has  ever  before  been  offered.  It  was  espe¬ 
cially  designed  for  use  with  the  self-centering  instrument  No.  93-230,  although  any  of  our  D’Arson- 
val  instruments  may  be  used  on  it.  For  lecture  table  demonstration  this  shelf  will  be  found  of 
especial  service.  For  this  work  we  recommend  the'use  of  the  bracket  only,  the  light  being  supplied 
from  the  Liliputian  Lamp,  No.  70-126. 

Wall  Bracket,  Telescope  and  Scale . $16.60 


93-242  GALVANOMETER  WALL-BRACKET  only,  without  Telescope  and  Scale .  $9.60 

93-246  GALVANOMETER  WALL-BRACKET,  TELESCOPE  and  SCALE  together  with  No.  93-230  SELF¬ 
LEVELING  D’ARSONVAL  GALVANOMETER  complete  as  illustrated .  48.60 

TELESCOPE.  See  No.  93-480. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


347 


SHUNTS 


No.  93-350 

93-350  ELEMENTARY  AYRTON  UNIVERSAL  SHUNT.  In  using  a  galvanometer  of  high  sensibility  it 
is  necessary  both  for  convenience  and  for  protection  of  the  galvanometer  to  use  some  device  for 
reducing  the  strength  of  the  current  through  the  galvanometer.  Separate  shunts  of  the  proper  re¬ 
sistance  may  be  used  to  bring  the  deflection  down  within  the  limit  of  the  scale,  but  where  it  is  desir¬ 
able  to  send  through  the  galvanometer  at  different  times  several  different  proportions  of  the  main 
current  the  separate  shunts  become  inconvenient.  The  instrument  abotfe  illustrated  provides 
in  compact  form  a  means  of  sending  small  or  large  fractions  of  the  main  current  through  the 
galvanometer,  merely  by  a  movement  of  the  contact  arm.  This  shunt  is  suitable  for  galva¬ 
nometers  with  ranges  from  50  to  500  ohms  resistance. 

Instrument  is  constructed  with  the  greatest  care,  coils  are  accurately  tested  before  shipment,  and  all 
parts  are  handsomely  and  durably  finished . 


No.  93-360 


93-360  UNIVERSAL  SHUNT.  A  great  advantage  of  this  shunt  over  the  one  preceding  is  that  it  can  be  used 
with  a  ballistic  galvanometer  as  well  as  with  a  dead-beat  instrument.  The  instrument  above 
illustrated  has  all  the  advantages  of  a  universal  form  and  in  addition  has  the  latest  improved 
sliding  contact  which  replaces  the  less  convenient  plug  arrangement.  The  contact  resistance  is 
very  low,  although  this  is  not  a  matter  of  great  importance  in  the  ordinary  use  of  the  instrument, 
as  the  contact  resistance  does  not  enter  the  galvanometer  circuit  proper.’  The  circuit  arrangements 
in  our  instrument  are  so  arranged  that  the  resistance  coils  are  also  available  as  a  “drop  wire,”  or 
simple  potentiometer  for  subdividing  a  potential  difference. 

This  instrument  has  received  the  most  painstaking  care  in  its  construction  as  well  as  design.  To 
protect  the  ebonite  top  from  air,  dust,  and  sunlight,  thus  preserving  its  insulating  properties,  a 
brass  cover  with  mahogany  top  similar  in  style  to  the  box  is  provided.  It  lifts  clear  away  from  the 
box  on  loosening  a  bayonet  catch  and  is  laid  aside  while  the  shunt  is  in  use. 

a  b  c 

Total  Resistance  10,000  20,000  100,000  ohms 

Each  ....  $28.50  38.00  62.00 

93-370  UNIVERSAL  SHUNT,  similar  to  above,  but  without  cover. 

a  b  c 

Total  Resistance  10,000  20,000  100,000  ohms 

Each . $25.00  34.50  68.50 


$7.50 


348 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


GALVANOMETER  ACCESSORIES 


93-400  PLANE  GALVANOMETER  MIRROR,  optically  plane,  diameter  Y*  inch  .  $1.00 

93-402  ONE-METER  CONCAVE  GALVANOMETER  MIRROR,  one-meter  focus,  diameter  'A  inch  1.25 

93-406  TWO-METER  CONCAVE  GALVANOMETER  MIRROR,  two-meters  focus,  diameter  A  inch  .  1.46 

93-416  NICKEL  SUSPENSION  FILAMENTS.  Owing  to  freedom  from  oxidation,  high  fusing  point,  and 
the  ability  to  draw  it  to  a  fineness  suitable  for  suspensions,  nickel  as  a  suspension  filament  has 
come  into  considerable  favor. 


3.  be  d  e 

Diameter . 001  .0015  .002  .003  .004  inch 

Per  Foot . $0.46  .40  .30  .25  .20 


93-426  PHOSPHOR-BRONZE  FILAMENTS.  Phosphor-bronze  has  been  used  with  success  as  suspensions 
in  the  highest  grade  electrical  instruments.  Owing  to  its  great  tensile  strength  and  non-magnetic 
qualities,  it  is  of  special  advantage  where  high  sensibility  is  desired. 


3  be  d  e 

Diameter . 001  .0015  .002  .003  .004  inch 

Per  Foot . $0.46  .40  .30  .25  .20 


93-436  STEEL  SUSPENSION  FILAMENTS.  Steel,  as  a  suspension,  is  free  from  “set”  and  has  great 

tensile  strength. 


3  be  d  e 

Diameter . 001  .0015  .002  .003  .004  inch 

Per  Foot . $0.40  .36  .30  .26  .20 


93-445 


WOLLASTON  WIRES,  the  finest  size  of  platinum  wire  filament;  the  wire  before  drawing,  is  en¬ 
closed  in  a  silver  sheath  and  is  drawn  through  a  jewel  gauge  (according  to  Wollaston)  until  the 
smallest  size  is  obtained.  The  silver  film  that  still  remains  must  be  removed  chemically  before 


the  wires  are  used. 

a 

b 

c 

Diameter  of  Platinum  Core  .... 

.  .  .  .00006 

.00008 

.0001  inch 

Approximate  External  Diameter  .  . 

.  .  .  .006 

.008 

.0036  inch 

Per  Foot  . 

.  .  .  $1.26 

1.00 

1.00 

93-460  DIRECT  READING  ADJUSTABLY 
MOUNTED  LAMP  AND  SCALE, 

“  Lin-o-Lite  ”  Lamp,  Opalescent 
Screen,  for  use  with  any  reflecting  gal¬ 
vanometer  to  give  direct  readings  of 
the  movement  of  the  coil. 

In  the  design  above  illustrated,  we  mount 
a  single  filament  incandescent  light 
within  a  cylindrical  tube,  the  glowing 
filament  showing  through  only  a  small 
opening  in  the  cylinder.  This  cylinder 
is  provided  with  a  clamp  for  attach¬ 
ment  to  the  supporting  rod  of  the  stand 
on  which  it  is  readily  adjustable.  The 
opalescent  screen  is  mounted  in  a  frame 
which  is  provided  with  a  rod  telescoping 
into  the  supporting  rod  of  the  stand. 

This  screen  has  a  scale  across  its  entire 
length  with  long  centimeter  divisions 
and  shorter  millimeter  divisions.  This 
scale  reads  both  ways  from  zero  in  the 
center.  All  parts  of  this  apparatus 
are  carefully  made  and  the  instrument 
has  been  of  great  utility  in  the  many 
laboratories  where  it  has  been  adopted. 

Complete  as  illustrated . $11.25 


No.  93-460 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


349 


MOUNTED  READING  TELESCOPE  AND  SCALE 

The  only  distinctive  items  illustrated  above  and  not  elsewhere  listed  are: 

93-470  READING  TELESCOPE  SCALE.  This  scale  is  printed  on  glazed  bristol  board,  50  centimeters  long, 
graduated  in  long  centimeter  divisions  with  shorter  millimeter  divisions  either  side  from  zero  at  the 
center,  figures  inverted.  This  scale  is  mounted  on  a  hardwood  strip  provided  with  clamp  for 
attachment  to  any  10-millimeter  rod .  $1.40 

93-480  READING  TELESCOPE  WITH  CROSS  HAIRS,  objective  18  millimeters  diameter,  focus  ]/2  to  one 
meter,  sliding  tube  focusing  adjustment.  This  telescope  is  carefully  constructed  of  the  best  ob¬ 
tainable  material,  the  optical  parts  having  been  calculated  to  a  nicety.  The  tubes  are  beautifully 
polished  and  lacquered  and  the  objective  is  furnished  with  a  brass  cap.  This  telescope  is  especially 


designed  for  use  in  electrical  measurements,  but  may  be  used  equally  as  well  in  experiments  on 

determining  the  magnifying  power  of  a  telescope .  6.00 

Other  apparatus  illustrated  above,  and  listed  elsewhere  is  as  follows: 

6-242  HARCOURT  SPECIAL  H-BASE,  for  19-millimeter  rod  .  .  $1.00 

6-20b  SUPPORT  ROD,  19  millimeters  diameter . 52 

6-770  HARCOURT  RIGHT  ANGLE  CLAMP . 96 

6-920  TELESCOPE  CLAMP . 2.45 

5-10b  SUPPORT  ROD,  10  millimeters  diameter . 18 

70-110  ELECTRIC  LAMP,  table  size,  adjustable  from  12  to  18  inches,  made  of  polished  brass,  nickel-plated. 

Complete  as  illustrated  in  Section  70 .  9.75 

70-112  GAS  LAMP,  similar  to  above,  but  arranged  for  burning  illuminating  gas. 

Complete  with  Argand  Burner  and  six  feet  of  rubber  tubing,  with  goose-neck  connection,  stand 

adjustable  from  12  to  18  inches .  9.75 

70-115  KEROSENE  LAMP,  similar  to  above,  but  arranged  with  reservoir  for  oil. 

Complete .  9-76 


For  LILIPUTIAN  PROJECTION  LAMP,  highly  recommended  as  a  source  of  light  for  galvanometer 
work,  see  page  241. 


\ 


350 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


D’ARSONVAL  TYPE  I 

1 

AMMETERS  AND  VOLTMETERS 

DOUBLE  RANGE 

•  '  m 


This  Double  Range  D’Arsonval  line  of  instruments  is  offered  as  a  distinctively  higher  grade  line  than  those 
which  have  been  commonly  used  by  students  in  laboratory  practice.  The  D’Arsonval  movement,  the  aging  of  the 
magnets,  the  adjusting  of  the  control  spring  and  jeweled  bearing,  are  features  to  which  special  attention  has  been 
given  by  our  best  instrument  makers. 

SCALE.  Each  instrument  is  made  with  two  scales  so  as  to  cover  as  wide  a  range  as  will  be  needed  in  any  kind 
of  work.  Each  scale  is  individual,  calibrated,  and  hand  drawn,  the  higher  range  drawn  in  black,  and  the  lower 
range  in  red  with  binding  posts  carefully  differentiated  to  avoid  burning  out  by  careless  connections.  The  zero  of 
each  scale  is  at  the  left,  giving  wide  scale  divisions. 

93-525  D’ARSONVAL  LABORATORY  AMMETER,  jewel  bearings,  aluminum  case,  hand  calibrated. 


Range  0-25  amperes,  scale  drawn  in  black;  0-5  amperes,  scale  drawn  in  red  . .  $9.40 

93-636  D’ARSONVAL  LABORATORY  VOLTMETER,  jewel  bearing,  aluminum  case,  hand  calibrated. 

Range  0-120  volts  in  2-volt  divisions  in  black,  0-12  volts  in  1/5  volt  divisions  in  red .  9.40 


WESTON  AMMETERS  AND  VOLTMETERS,  LABORATORY  TYPE 

93-660  DOUBLE  RANGE  AMMETER,  0—25  amperes 

0-5  amperes  . $16.26 


93-560  DOUBLE  RANGE  VOLTMETER,  0-150  volts 

0-15  volts 


16.25 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


351 


THE  REMOVABLE  SHUNT  TRIPLE  RANGE 

VOLT-AMMETER 


No.  93-600 

Patent  Pending 


Our  Universal  Voltmeter  and  Ammeter  has  been  designed  to  give,  in  practical  working  form,  all  the  ranges  re¬ 
quired  in  such  work  as  is  usually  taken  in  technical  school  and  vocational  school  laboratories,  one  instrument  serv¬ 
ing  the  purpose  of  six  of  the  usual  form  commercial  type.  By  this  means  it  is  possible  to  supply  a  complete  work¬ 
ing  equipment  for  an  entire  laboratory  division  covering  the  ranges  required  for  all  practical  measurements  at  an 
expense  well  within  the  reach  of  the  average  school  desiring  to  give  instruction  in  practical  electrical  measurements. 

This  instrument  is  of  a  distinctly  high  grade  and  designed  for  practical  work,  every  possible  provision  having 
been  made  against  liability  of  injury.  Should,  in  the  course  of  rough  handling,  the  pointer  be  moved  slightly  from 
zero,  ample  provision  has  been  made  for  ready  re-setting,  insuring  the  same  degree  of  accuracy  as  the  instrument 
originally  had. 

The  ranges  covered  are  as  follows:  — 


Voltmeter,  0-150  volts, 
0-15  volts, 

0-3  volts, 

Ammeter,  0-30  amperes, 
0-15  amperes, 
0-3  amperes. 


Voltmeter.  The  resistances  giving  the  various  ranges  are  permanently  attached,  each  brought  out  to  its  ap¬ 
propriate  binding  post,  and  cannot,  therefore,  be  disconnected. 

Ammeter.  The  various  ranges  of  ampere  needs  are  met  by  the  use  of  our  new  form  interchangeable  shunt, 
the  same  as  used  in  our  Universal  Galvanometer  No.  93-130. 

Additional  shunts  may  be  supplied,  if  desired,  giving  other  ranges  than  those  specified.  Shunts  which  are  not 
in  use  are  carried  on  the  inside  of  the  base,  as  noted  in  the  illustration. 

Mounting.  Both  the  cap  and  base  are  of  aluminum.  The  base  is  made  separable  to  provide  carrying  space 
for  the  shunts  not  in  use. 

Binding  Posts.  Each  binding  post  is  clearly  marked,  giving  use  and  range  for  which  it  is  designed,  thus  avoid¬ 
ing  possibilities  of  error  resulting  from  wrong  connections. 

Scales.  Various  scales  are  carefully  diSerentiated  so  that  no  error  may  be  introduced  into  the  work  by  care¬ 
lessness  in  reading.  It  will  be  seen  that  we  have  covered  in  a  most  satisfactory  way  the  six  most  important  ranges 
of  laboratory  instruments  and  provided  against  every  possible  contingency  in  practical  use. 

93-600  THE  REMOVABLE  SHUNT  TRIPLE  RANGE  VOLT-AMMETER  . $20.00 


WESTON  TRIPLE  RANGE  AMMETERS  AND  VOLTMETERS, 

LABORATORY  TYPE 

93-626  TRIPLE  RANGE  VOLT-AMMETER,  laboratory  type,  covering  three  ranges  of  Voltmeters,  three 
ranges  of  Ammeters,  as  follows:  — 

Volts,  0-150 
0-15 
0-3 

Amperes,  0-30 
0-3 

0-1  # .  29.76 


352 


L.  E.  KNOTT  APPARATUS  CO  ,  BOSTON 


THE 


No.  93-635 

MULTIPLE  RANGE  ROTARY  METER 

FOR 

DIRECT  CURRENT 


Range,  0-30  and  0-3  Amperes,  0-100  Mill  Volts  (1-10  Volts) 
0-1-10,  0-3  and  0-30  Volts 


No.  93-636 


The  Multiple  Range  Rotary  Meter  is  a  portable  universal  measuring  instrument  4 inches  X  3  inches  X  2 
inches  high,  a  most  convenient  size  for  either  instructor’s  or  students’  use. 

The  instrument  is  provided  with  six  binding  posts,  clearly  differentiated,  yet  so  designed  that  even  after  con¬ 
nections  are  made  to  the  appropriate  posts,  no  current  passes  until  the  body  of  the  instrument  is  turned  in  its 
socket  so  that  the  pointer  rests  on  the  desired  range  designated  on  the  graduated  surface  which  surrounds  the  body 
of  the  instrument,  thus  providing  a  double  protection  against  accidental  injury. 

The  base  of  the  instrument  contains  a  commutator  which  is  stationary,  mounted  in  a  suitable  receptacle  having 
provision  for  a  number  of  shunts  and  resistances,  connections  with  which  are  made  through  the  several  segments 
of  the  commutator. 

A  Milvoltmeter  is  centrally  pivoted  to  the  commutator  in  such  a  way  that  the  meter  terminal  makes  connec¬ 
tion  with  successive  segments  of  the  commutator  as  the  meter  is  rotated  on  its  axis.  A  fixed  index  finger  on  the 
side  of  the  knurled  meter  case  shows  the  position  of  this  terminal  and  suitable  markers  on  the  surface  of  the  com¬ 
mutator  receptacle  show  the  position  of  the  segments. 

No  current  passes  through  the  meter  unless  the  index  finger  points  to  the  marker  corresponding  with  the  bind¬ 
ing  post  connected  with  the  source  of  current,  thus  greatly  lessening  the  danger  of  damaging  the  instrument  by 
overloading  it  through  a  wrong  connection. 

This  invention  practically  reduces  the  problem  of  making  a  voltammeter  with  a  number  of  scales  to  the  sim¬ 
plicity  of  a  low  range  single  scale  voltmeter,  and  should  repairs  be  necessary,  the  probability  of  having  to  alter  the 
adjustment  of  the  extra  shunts  or  resistances  is  very  remote,  a  statement  that  cannot  be  made  concerning  the  con¬ 
ventional  type  of  voltammeter. 

In  the  conventional  type  of  voltammeter  where  the  same  moving  system  is  utilized  for  current  and  voltage 
measurements,  it  is  necessary  to  have  two  distinct  windings  on  the  moving  coil  and  separate  means  of  conducting 
the  current  to  these  windings,  or  else  provide  a  switch  in  the  moving  system  circuit  to  break  the  ammeter  circuit 
when  it  is  desired  to  measure  voltage,  either  of  which  methods  introduces  complications  which  are  both  expensive 
and  unreliable. 

In  the  Rotary  Meter  there  is  but  one  winding  in  the  moving  system  and  one  pair  of  conductors  from  the  moving 
system  to  the  contact  terminals  and  these  consist  of  two  coil  springs  which  serve  the  double  purpose  of  carrying 
the  current  to  the  coil  and  furnish  the  controlling  force  of  the  movable  member.  All  other  coils  and  shunts  are  con¬ 
tained  in  the  commutator  receptacle  each  with  its  own  circuit  from  the  binding  post  to  the  corresponding  segment 
of  the  commutator.  This  appears  to  be  the  last  word  in  safety,  simplicity  and  accuracy. 

Instead  of  a  multitude  of  coils  and  shunts  crowded  together  in  one  case  and  an  array  of  binding  posts  all  con¬ 
nected  permanently  to  the  moving  system  inviting  wrong  connections,  or  a  collection  of  coils  and  shunts,  each  sep¬ 
arate  and  by  itself,  an  inconvenience  that  few  are  willing  to  tolerate,  the  Rotary  Meter  combines  in  a  convenient 
form  the  necessary  coils  and  shunts  each  one  in  its  own  compartment  and  connected  with  a  commutator  which  makes 
connection  at  will  with  the  simplest  form  of  indicating  instrument  that  has  yet  been  devised,  and  the  whole  occupy¬ 
ing  a  space  only  4 x  3  x  2  inches. 

Price 


$16.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


353 


VOLT-  AMMETERS 

MAGNETIC  VANE  TYPE 


Volt-ammeters.  The  line  of  Volt-ammeters  which  we  list  herewith  is  of  the  well-known  magnetic  vane  type 
with  zero  center  which  avoids  injury  in  case  of  wrong  connections.  This  is  a  type  of  instrument  which  will  com¬ 
mend  itself  to  Physics  teachers  because  of  the  readiness  with  which  the  student  may  obtain  results  reading  directly 
in  the  fundamental  units  of  Volts  and  Amperes,  thus  learning  at  the  very  beginning  of  his  work  the  significance  of 
the  common  commercial  terms. 

Double  scale,  jewel  bearing,  aluminum  case  with  hand  calibration,  combine  to  give  this  instrument  a  value  in 
laboratory  work  not  equaled  by  any  other  medium-priced  instrument  on  the  market. 

Ranges.  The  ranges  selected  are  such  as  will  be  of  the  widest  service  in  laboratory  work. 

93-650  VOLT-AMMETER,  magnetic  vane  type,  jewel  bearing,  aluminum  mounting,  range  10  volts  and  10 


amperes .  . $6.60 

93-670  VOLT-AMMETER,  magnetic  vane  type,  range  120  volts  and  15  amperes .  8.60 


NEW  LINE  OF  ALTERNATING  CURRENT  AMMETERS  AND 

VOLTMETERS 

It  is  doubtless  due  to  the  great  advance  which  has  been  made  during  the 
past  few  years  in  the  production  of  iron  with  definite  electrical  qualities,  that 
the  alternating  current  measuring  instrument  has  now  reached  its  present  high 
state  of  perfection.  It  is  with  pleasure  that  we  call  the  line  we  here  ofier  to  the 
attention  of  laboratory  workers. 

Voltmeter.  A  thoroughly  reliable  Voltmeter  giving  a  full  scale  deflection 
on  15  volts,  a  voltmeter  of  higher  resistance  than  is  commonly  used  in  com¬ 
mercial  instruments. 

Ammeter.  Our  alternating  current  Ammeters  will  measure  with  commer¬ 
cial  accuracy  the  output  of  magnetos  and  even  the  smallest  size  alternating  current 
generators.  The  Ammeters  in  this  class  are  of  much  lower  resistance  than  the 
conventional  type  of  alternating  current  instruments. 

Mounting.  These  instruments  are  mounted  in  a  7-inch  finely  finished  iron  case  with  nickel  trimmings  and  in 
the  usual  switchboard  form.  See  the  illustration  above. 


93-700  VOLTMETER,  7-inch  case,  0-15  volts . $14.00 

93-710  - f  0-125  volts . 14.26 

93-720  - ,  0-500  volts . 19.00 

93-740  AMMETER,  7-inch  case,  0-1  ampere . 13.00 

93-750  - ,  0-5  amperes . 13.60 

93-760  - ,  0-25  amperes . 13.50 

93-770  - ,  0-100  amperes . 13.76 


354  L .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ELECTRICAL  RESISTANCE  APPARATUS 

RESISTANCE  COILS 


No.  94-20  No.  94-21 


No.  94-30 


No.  94-60 


94-20  ONE-OHM  RESISTANCE,  after  Millikan  and  Gale’s  “A  Laboratory  Course  in  Physics”  (Exper¬ 


iment  33) . $0.28 

94-21  THOUSAND-OHM  RESISTANCE  COIL,  after  Millikan  and  Gale’s  “A  Laboratory  Course  in 

Physics”  (Experiments  31  and  32) .  .45 

94-30  SPOOL  RESISTANCES.  These  spools  are  practically  the  same  as  those  which  are  used  in  our  high- 
grade  resistance  boxes.  They  are  guaranteed  to  be  accurate  to  %  of  one  per  cent. 

abcdef  ghij  klmn  o  p  q 


Resistance  1  2  3  4  10  20  30  40  50  100  200  300  400  1000  2000  3000  4000  Ohms 

Each  .  $0.50  .55  .65  .55  .60  .62  .65  .68  .76  .80  .85  .95  1.00  1.50  1.75  2.00  2.20 

94-60  TEMPERATURE  COIL  for  use  with  Wheatstone  Bridge  in  the  study  of  effect  of  temperature  changes 

on  the  resistance  of  a  coil  of  wire. 

This  instrument  consists  of  a  spool  of  insulating  material  on  which  is  mounted  a  coil  of  high  resistance, 


the  ends  of  which  are  terminated  in  heavy  leads. 

Complete  as  illustrated . $1.20 

94-61  TEMPERATURE  COIL,  after  Turner  and  Hersey  (Experiment  E081) .  .15 


No.  94-70 


94-70  RESISTANCE  COILS,  HYDE  FORM,  for  use  with  Wheatstone  Bridges,  in  determining  the  resistances 
of  coils;  also  for  formulating  laws  of  resistance  in  wires.  In  our  new  design  we  have  entirely  ob 
viated  the  danger  of  the  ends  of  the  coil  becoming  detached  from  the  leads,  —  a  very  great  ad¬ 
vantage  over  the  old  forms. 

As  illustrated,  this  instrument  consists  of  eight  spools,  of  different  lengths  and  different  diameters 
and  two  different  materials.  Each  spool  is  mounted  on  a  pin  fixed  in  a  neatly  finished  baseboard. 

To  simplify  the  deriving  of  the  laws  of  resistance  we  furnish  eight  spools  capable  of  securing  the  follow¬ 
ing  combinations:  — 

2  Spools,  same  material,  same  diameter,  same  length. 

2  Spools,  same  material,  same  length,  different  diameters. 

2  Spools,  same  material,  same  diameter,  but  one  double  the  length  of  the  other. 

2  other  Spools  which,  with  combination  with  those  above  cited,  will  allow  of  comparison, 
of  same  diameter  and  same  material,  but  of  lengths  as  1:  2:  3:  4:  5. 

1  other  Spool  of  same  diameter  but  different  material  from  one  of  the  above  named,  but  exactly 
ten  times  the  length. 

Set  of  eight  spools  complete,  mounted  on  base  as  illustrated . 


$3.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


355 


No.  94-80  No.  94-90 


94-80  RESISTANCE  SPOOLS.  Set  of  five  spools  of  unknown  resistance,  all  mounted  on  same  spindle 
on  a  polished  wood  base,  each  with  binding  posts  for  connections  to  each  or  to  all  in  the  series. 

This  combination  consists  of  the  following  spools:  Copper  Wire —  10  meters,  Nos.  22  and  28,  and 
20  meters,  Nos.  22  and  28;  German  Silver —  10  meters,  No.  22 . Per  Set 

94-90  RESISTANCE  BOARD,  after  C.  H.  Andrews  of  the  South  High  School,  Worcester,  Mass. 

This  instrument  consists  of  four  bobbins,  the  wire  so  wound  and  connected  as  to  make  possible  com¬ 
binations  as  follows:  2  coils  of  same  length  and  material,  but  of  different  diameter;  2  coils  of  same 
length  and  diameter  but  of  different  material,  and  2  coils,  same  diameter  and  material,  but  of  differ¬ 
ent  lengths. 

In  the  design  of  this  instrument  Mr.  Andrews  has  taken  pains  to  select  wires  the  diameters  and  re¬ 
sistances  of  which  have  convenient  ratios  to  each  other  and,  therefore,  best  suited  for  use  in  parallel. 

The  coils  have  the  further  advantage  that  they  are  so  connected  to  the  brass  blocks  that  combina¬ 
tions  in  series  or  parallel  of  any  one  or  more  of  the  coils  may  be  secured  by  proper  placing  of  the 
plugs  in  their  tapered  holes. 

This  instrument  is  very  carefully  constructed;  the  plugs  are  nicely  tapered  and  ground  to  fit  the  holes. 

Mounted  as  illustrated  on  a  finished  hardwood  base . 

94-96  CULLER’S  DOUBLE  RHEOCHORD.  This  outfit  consists  of  a  pair  of  Rheochord  Boards,  finished, 
provided  with  wire  and  binding  posts;  character,  size,  length  and  method  of  winding  the  wires  as 
indicated  in  Culler’s  “Laboratory  Manual  of  Physics”  (Experiment  XLVc) . Pair 

94-97  FULLER  AND  BROWNLEE  RHEOCHORD  BOARD,  as  specified  in  Fuller  and  Brownlee’s  “Labo¬ 
ratory  Exercises”  (Experiment  73) . , . 

94-98  RHEOCHORD  BOARD,  as  specified  in  Millikan,  Gale  and  Bishop’s  “Laboratory  Physics”  (Ex¬ 
periments  32  and  36) . ) . 

STANDARD  RESISTANCES.  The  coil  illustrated  has  been  designed  for  use  when¬ 
ever  the  highest  accuracy  is  not  required,  and  the  inconvenience  attending  the 
use  of  an  oil  bath  can  therefore  be  avoided.  Though  not  intended  as  the  highest 
standards,  the  accuracy  and  compactness  make  these  coils  convenient  for  many 
purposes.  The  winding  is  a  matter  of  great  care;  the  wire  used  is  manganin, 
and  the  core  on  which  the  coil  is  wound  is  of  brass.  This  core  is  open  at  each 
end,  giving  ventilation  as  well  as  preventing  changing  of  temperature;  also  per¬ 
mitting  the  introduction  of  a  thermometer  into  the  interior.  The  winding  is  ar¬ 
ranged  in  a  thin  layer  on  the  core  and  insulated  with  only  sufficient  wax  to  prevent 
access  of  the  air  to  the  wire. 

The  case  is  of  brass;  the  terminals  are  heavy  copper  rods  giving  ample  conductivity 
and  contact  surface.  The  lower  ends  of  these  rods  are  arranged  to  dip  into  mercury 
cups,  while  the  upper  ends  are  equipped  with  large  binding  posts  screwing  into 
the  copper  bars  and  bearing  against  lugs  which  give  ample  clamping  surface. 
These  coils  are  furnished  in  four  different  sizes  as  listed  below.  They  are  accu¬ 
rately  adjusted  to  %  of  one  per  cent.  With  each  coil  a  certificate  of  accuracy 
giving  the  date,  temperature,  and  precise  value  of  the  resistance  at  the  final  test 
is  included. 

a  b  c  d 

Capacity  .  1  10  100  1000  Ohms 

.  Each  . $10.00  10.60  12.60  16.60 

94-106  STANDARD  RESISTANCES,  same  as  above,  but  adjusted  to  an  accuracy  of  of  one  per  cent.  With 
these  coils  the  certificate  is  not  furnished. 

a  b  '  c  d 

Capacity .  1  10  100  1000  ohms 

Each .  $7.60  8.00  9.60  12.60 


$2.90 


3.90 

6.76 

4.66 

4.65 


356 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


STANDARD  RESISTANCES 


Nos.  94-116  to  94-117 


94-116  STANDARD  RESISTANCES,  Reichsanstalt  Form,  universally  accepted  for  work  of  high  precision. 

These  have  been  evolved  as  an  embodiment  of  the  long  experience  of  the  German  Government 
Bureau.  The  resistance  material  of  these  standards  is  manganin,  selected  not  only  for  its  approved 
permanence  and  low  temperature  resistance  coefficient,  but  also  for  its  small  thermo-electro-motive 
force  against  copper.  The  external  case  is  not  in  connection  with  the  winding  and  furnishes  merely 
a  mechanical  support  and  protection.  The  standard  may  be  immersed  in  oil  so  that  the  coil  is  com¬ 
pletely  submerged,  and  the  case,  bobbin,  and  winding  are  so  arranged  that  the  oil  has  access  to  all 
parts  of  the  coil,  making  it  possible  to  ascertain  or  control  its  temperature  with  certainty.  An  open¬ 
ing  through  the  ebonite  top  permits  the  insertion  of  a  thermometer  into  the  interior.  Case  and  ter¬ 
minals  are  nickel-plated  to  prevent  corrosion.  Every  operation  of  the  construction  of  these  stand¬ 
ards,  winding,  aging,  and  adjustment,  is  most  carefully  carried  out.  Our  standards  will  there¬ 
fore  be  found  not  merely  accurate  in  adjustment  but  also  permanent  in  calibration.  Each  coil 
is  adjusted  to  Vioo  of  one  per  cent,  of  the  value  of  our  copies  of  the  United  States  Standard.  With 
each  resistance  sent  out  is  a  certificate  of  accuracy  for  each  coil. 


abed  e 

Capacity  .  1  10  100  1000  ohms 

Each . $46.00  46.00  46.00  46.00  46.00 


94-117  STANDARD  RESISTANCES,  Reichsanstalt  Form,  same  accuracy  and  general  struc¬ 
ture  as  above,  but  arranged  for  air  cooling  only. 


a  b  c  d 

Capacity  .  1  10  100  1000  ohms 

Each . $20.00  20.00  20.00  22.60 


94-126  SINGLE-COIL  TENTH  MEGOHM.  In  the  construction  of  this  box  we  use 
one  of  the  units  of  our  Standard  Megohm  Box  No.  94-226,  mounted  in  a 
cylindrical  brass  case  with  raised  terminals,  thermometer  hole,  and  offered  in 
form  as  illustrated. 

Tenth  Megohm  Coil  as  illustrated . $36.00 


No.  94-126 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


357 


RESISTANCE 


Nos.  94-152  to  94-155 


BOXES 


No.  94-160 


94-160  SCHOOL  RESISTANCE  BOX,  range  1  to  20  ohms,  guaranteed  accuracy  of  3^  of  one  per  cent.  .  $3.75 

94-162  SCHOOL  RESISTANCE  BOX,  range  3^  to  111  ohms,  guaranteed  accuracy  of  3/£  of  one  per  cent.  7.60 

94-165  -  — ,  same  as  above,  but  with  certificate  from  our  electrical  laboratory  . . 10.00 

94—160  SCHOOL  DEMONSTRATION  RESISTANCE  BOX.  This  box  is  the  same  as  above,  but  supplied 
with  glass  front  and  back  that  students  may  see  the  internal  construction  of  a  resistance  box. 

By  this  method  the  coil  connections  may  readily  be  observed,  and  the  pupil  is  enabled  to  judge 

for  himself  the  structure  of  an  ordinary  resistance  box .  9.50 

94-170  B-P  SWITCH  RESISTANCE  BOX.  The  illustration 
above  shows  our  resistance  box  fitted  with  the  new 
B-P  Switch  in  which  we  believe  a  great  step  has 
been  taken  in  the  proper  direction,  for  this  simple 
device  comprises  the  good  points  of  the  plug  and 
associates  with  them  the  valued  features  of  a  switch 
mechanism.  In  the  design  of  the  switch  care  has 
been  taken  to  retain  only  the  good  features  and  it 
will  be  found  both  rapid  and  dependable  in  accurate 
work. 

POINTS  OF  MERIT 

1.  One  throw  of  the  hand  puts  a  coil  in  or  out  of  cir-  No.  94-170 

cuit  as  desired. 

2.  The  closing  of  the  switch  is  always  accompanied  with  a  wedging  rubbing  action  similar  to  that 

met  with  in  perfectly  fitted  plugs. 

3.  The  resistance  of  the  closed  switches  is  extremely  low. 

4.  It  is  not  necessary  to  open  the  switches  when  not  in  use,  as  the  expansion  of  the  rubber  upon 

which  they  are  mounted  can  do  no  harm. 

5.  There  arc  no  loose  parts  to  become  lost  or  mixed. 

6.  The  values  of  the  coils  in  or  out  of  circuit  can  be  told  at  a  glance. 

7.  The  values  of  the  coils  are  marked  upon  the  switch  blade  handles,  which  are  always  up  in  plain 

sight  when  open,  so  that  it  is  not  necessary  to  get  directly  over  the  box  to  obtain  their  values. 

8.  Portions  of  the  switch  device  extend  through  the  top  of  the  resistance  box  and  are  directly  soldered 

to  the  coil  terminals,  thereby  insuring  against  unreliable  screw  contact  joints,  etc. 

9.  The  simplicity  of  construction  enables  drawn  metal  of  unusually  low  and  uniform  resistance  to 

be  used  to  advantage. 

10.  There  is  no  chance  for  dirt  and  filings  to  lodge  and  short-circuit  the  coils. 

11.  It  is  very  rapid. 

12.  Perfection  of  contact  does  not  depend  upon  accurately  reamed  contact  surfaces  that  may  be 

badly  injured  by  use  or  abuse. 

The  coils  contained  in  this  box  are  made  and  tested  by  our  standard  process,  and  their  accuracy  is 
fully  equal  to  that  of  any  box  on  the  market.  The  coils  are  each  guaranteed  accurate  to  3^  of  one 
per  cent.  The  total  resistance  is  1 1 1  ohms  divided  as  follows:  —  0.1,  0.2,  0.3,  0.4,  1,  2,  3,  4,  10,  20, 

30,  40  ohms . $6.90 


358 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


94-180  SUPERIOR  ROUND  FORM  PLUG 
RESISTANCE  BOX.  This  box  is 
an  excellently  finished,  reasonably 
priced  high-grade  instrument.  Con¬ 
tains  13  coils  ranging  from  H  to  50 
ohms,  with  total  resistance  of  161 
ohms.  Each  instrument  is  guaran¬ 
teed  accurate  to  within  M  to  %  of 
one  per  cent . $7.80 


No. 


No.  94-190 


94-190 


94-196 


TRAVELING  PLUG  RESISTANCE  BOX.  This  box  is  provided  with  extra  heavy  brass  blocks  and 
reinforced  ebonite  top.  Contains  12  coils  ranging  from  1  to  400  ohms,  with  total  resistance  of 
1110  ohms.  The  usefulness  of  the  instrument  is  increased  by  the  addition  of  two  traveling  plugs 
facilitating  its  use  in  the  comparison  of  electro-motive  force  of  batteries,  and  other  tests.  Guar¬ 
anteed  accuracy  of  }/i  to  3io  of  one  per  cent . 

TRAVELING  PLUG  RESISTANCE  BOX,  similar  to  above  but  constructed  for  greater  range. 
Contains  16  coils  ranging  from  1  to  4000  ohms  with  total  resistance  of  11,110  ohms.  Guaranteed 
accuracy  of  K  to  %  of  one  per  cent . 


$26.00 

30.00 


No.  94-200d 

94-200  DECADE  RESISTANCE  BOX,  with  sliding  contact  and  connections;  best  material,  highest  ac¬ 
curacy,  improved  positive  contact  secured  by  the  laminated  contact  brushes. 

abed 


No.  of  Decades  ...  3  4  5  6 

Each . $90.00  118.00  140.00  166.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


359 


MEGOHM  BOX 


No.  94-226 


94-225  STANDARD  MEGOHM  BOX,  range  10,000  to  1,000,000  ohms,  an  arrangement  for  a  megohm  re¬ 
sistance  which  gives  the  greatest  attainable  flexibility  and  convenience  without  diminishing  the 
accuracy. 

General  Arrangement.  Highly  insulated  binding  leads,  easily  accessible  buss  bars  for  changing  of 
the  connections.  A  total  resistance  of  one  megohm  is  obtained  by  putting  10  coils,  each  of  100,000 
ohms,  in  series.  Joining  in  multiple,  a  minimum  resistance  of  10,000  ohms  is  obtained.  Any 
range  between  the  two  in  steps  of  10,000  ohms  is  readily  obtained.  The  importance  of  this  ar¬ 
rangement  in  accurate  comparisons  of  high  resistances  cannot  be  overestimated. 

Insulation.  Perfect  insulation  is  a  requisite  in  all  high  resistance  work.  As  will  be  noted,  the  box 
is  made  of  large  proportions,  raised  ebonite  insulated  terminals,  so  designed  as  to  be  easily  cleaned. 

This  feature  should  not  be  overlooked  in  practical  work.  The  box  is  also  provided  with  a  cover, 
not  shown  in  the  illustration.  This  feature  we  consider  essential  in  order  that  the  insulating  quali¬ 
ties  of  the  ebonite  may  be  retained. 

Connections.  Note  the  new  sliding  link  running  from  buss  bars  to  binding  posts.  This  adds  greatly 
to  the  convenience  of  connecting,  insures  against  any  of  the  connectors  being  lost  and  makes  it 
possible  to  attain  quickly  the  necessary  changes  in  the  least  possible  room. 

Coils.  The  coils  are  wound  non-inductively  with  our  special  “B”  high  resistance  wire,  which  we 
consider  for  purposes  of  a  megohm  box  superior  to  manganin  as  used  in  all  of  our  low  range  boxes. 

Each  coil  is  thoroughly  protected  from  moisture  by  wax  and  insulating  covering,  which  also  seems  to 
give  to  each  unit  ability  to  withstand  mechanical  strains. 

Standard  Megohm  Box . $140.00 

94-230  STANDARD  TENTH  MEGOHM  BOX.  We  have  had  frequent  calls  for  a  box  similar  to  our  No. 

94-226,  but  utilizing  the  Wolff  method  of  connecting  and  other  features  in  its  construction,  but  of 
lower  range.  We  therefore  offer  the  same  box  with  the  same  number  of  coils  but  of  lower  unit 
denomination,  making  the  total  resistance  of  the  box  J(o  megohm.  Each  coil  has  a  resistance  of 
10,000  ohms;  100,000  ohms  may  be  secured  by  connection  in  series,  1,000  ohms  by  connection  if 
in  multiple. 

Standard  Tenth  Megohm  Box . 100.00 

Standard  Tenth  Megohm  Coil.  See  No.  94-126. 


360 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


f 


COMBINED  BRIDGE  AND  RESISTANCE 

BOXES 


No.  94-250 


94-250  RATIO  BOX.  In  Wheatstone  Bridge  work  it  is  essential  that  easily  accessible  ratio  arms  be  pro¬ 
vided.  This  box  has  been  designed  for  this  particular  purpose.  It  contains  six  coils  as  follows:  — 

1,  10,  100,  100,  10,  and  1  ohms,  which  will  give  nine  different  working  ratios.  Each  coil  is  guaran¬ 
teed  accurate  to  of  one  per  cent.  It  may  therefore  be  seen  that  with  this  accuracy  the  ratio  box 
may  be  used  as  a  standard  resistance  of  222  ohms  capacity . . . $10.60 


No.  94-260 


No.  94-270 


94-260  ROUND  TYPE  PLUG  BRIDGE  AND  RESISTANCE  BOX.  Contains  13  coils  ranging  from  %  ohm 

to  50  ohms,  giving  a  total  resistance  of  161  ohms,  in  addition  to  the  bridge  coils  which  have  the 
following  resistance  of:  100,  10,  1,  1,  10,  and  100  ohms.  It  may  therefore  be  seen  that  the  total 
range  is  from  .001  ohm  to  17,600  ohms.  This  instrument  is  recommended  as  one  of  great  accuracy, 
giving  a  wide  range.  Guaranteed  accuracy  of  %  to  of  one  per  cent . $18.50 

94-270  IMPROVED  COMBINED  BRIDGE  AND  RESISTANCE  BOX.  Bridge  coils  are  1,  10,  100,  100, 

10,  and  1  ohms.  Resistances  range  from  1  to  400  ohms.  Total  resistance  1110  ohms.  Total  range  of 
measurements  from  .01  ohm  to  111,000  ohms.  Guaranteed  accuracy  to  %  of  one  per  cent.  .  .  25.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


361 


Mr-280  ZIEGLER  BRIDGE  AND  RESISTANCE  BOX.  This  box  has  been  especially  designed  to  meet  the 
constant  demands  for  a  reliable  and  conveniently  arranged  combined  box  giving  a  wide  range,  yet 
one  which  can  be  furnished  at  a  price  within  the  appropriation  of  most  schools. 

The  first  row  of  the  resistance  box  contains  nine  j^-ohm  coils;  the  second  10  1-ohm  coils;  the  third 
ten  10-ohm  coils.  The  total  range  of  measurement,  therefore,  is  from  .001  ohm  to  11,090  ohms. 
Separate  keys  properly  connected  for  battery  and  galvanometer  are  mounted  as  illustrated.  Coil 
accuracy  guaranteed  to  3lo  of  one  per  cent . 


No.  94^285 


94-286  ZIEGLER  IMPROVED  COMBINED  BRIDGE  AND  RESISTANCE  BOX.  This  box  is  in  general 
similar  to  No.  94-280.  It  has,  however,  a  larger  capacity  and  the  blocks  are  extra  heavy.  The 
bridge  coils  are  1000,  100,  10,  1  ,100,  1000  ohms.  The  resistance  box  coils  range  from  %  ohm  up  to 
4,000  ohms.  Total  resistance  11,111  ohms.  Range  .0001  ohm  to  11,110,000  ohms.  Coil  accuracy 
guaranteed  to  %  of  one  per  cent . 


$34.76 


$60.00 


362 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PRECISION  RESISTANCE  BOX  AND  BRIDGE 


No.  94-300 

94-300  STANDARD  PRECISION  RESISTANCE  BOX,  designed  to  give  the  highest  degree  of  precision 
of  which  the  plug  contact  form  of  Wheatstone  Bridge  is  capable;  constructed  to  furnish  the  best 
that  modern  research  has  produced. 

Range.  The  one-ohm  Ratio  Coil  can  be  thrown  into  either  arm  desired  by  means  of  one  of  the  trav¬ 
eling  plugs  supplied  with  the  box.  The  range  of  the  bridge  is,  therefore,  from  .001  to  11,110,000 


ohms. 

Resistance  Arms  — 

1 

10 

100 

1000  ohms 

2 

20 

200 

2000  “ 

3 

30 

300 

3000  “ 

4 

40 

400 

4000  “ 

Bridge  Arms  — 

1 

10 

100 

1000  ohms 

Total  .  . 

10 

100 

1000  “ 

Accuracy.  All  the  features  tending  to  give  permanency  of  calibration  as  well  as  accuracy  have 
been  studied  in  every  detail.  The  coils  in  the  ratio  arms  are  adjusted  to  %  of  one  per  cent.;  those 
in  the  ratio  arms  to  V20  of  one  per  cent.  With  a  proper  handling  of  this  box,  results  may  be  secured 
limited  only  by  the  inherent  capabilities  of  the  plug  contact  form. 

For  details  of  construction,  see  special  circular  which  will  be  mailed  upon  request. 

SPECIAL  FEATURES 

Coils  of  manganin  wire,  aged  by  our  special  process,  wound  on  hollow  brass  bobbins,  securing  per¬ 
fect  insulation  and  greater  carrying  capacity,  individually  tested,  and  attached  by  special  arms, 
permitting  new  coils  to  be  furnished  and  attached  by  user. 

The  Insulation  is  of  the  very  highest  quality,  interior  of  box  practically  moisture  proof  to  insure 
permanency  of  insulation. 

Connecting  Blocks  of  unusually  large  size,  of  ample  clearance  and  special  provision  for  cleaning. 

Traveling  Plugs,  —  two  furnished  with  each  box. 

Coil  Plugs,  rubber  handles,  diamond  form;  tapers  designed  for  constant  use  without  contact  error. 

Grid  Support,  on  interior  of  box  to  prevent  springing  of  top  by  excess  plug  pressure. 

Cover.  Dust-tight,  provided  with  each  box  to  insure  life  of  rubber  top. 

Standard  Precision  Resistance  Box,  as  above  described . 


$110.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


363 


Patents  Pending 

UNIVERSAL  LECTURE  TABLE  RHEOSTAT 
AND  RESISTANCE  FRAME 

A  Group  Cut  Illustrating  the  Following  Numbers 

In  designing  the  above  apparatus  we  had  two  primary  objects  in  mind;  first,  to  make  available  an  easily  un¬ 
derstood,  readily  controllable  rheostat,  which  could  not  get  out  of  order,  designed  for  use  on  110  volt  current;  second, 
a  satisfactory  method  of  teaching  the  effect  of  different  methods  of  lamp  connections  in  the  electrical  circuit. 

Should  the  instructor  not  care  to  have  the  light  which  comes  from  the  lamps  when  used  as  resistances,  dark  units 
as  illustrated  are  now  available,  giving  currents  of  from  0.6  to  5  amperes  each,  so  that  combining  these  in  multiple 
and  in  series,  a  wide  range  of  current  may  be  obtained  graded  in  small  steps,  as  the  instrument  itself  will  carry  from 
50  to  75  amperes  with  perfect  safety. 

In  outfit  No.  94-350  lamps  only  are  furnished  and  the  outfit  may  well  be  called  a  Universal  Lamp  Resistance 
Board,  giving  ampere  strengths  from  0.2  to  6.00  amperes. 

A  wide  range  of  ampere  values  may  be  secured  by  using  the  resistance  units  in  series,  multiple  or  series-multiple 
arrangement.  Outfits  Nos.  94-363  to  94-358  are  supplied  with  resistance  units  only.  These  outfits  are  recommended 
for  all  laboratory  resistance  work. 

The  fuse  plugs  have  negligible  resistances  and  are  used  for  facilitating  connections. 

The  value  of  the  apparatus  as  a  practical  rheostat  of  wide  ampere  ranges  is  greatly  enhanced  by  its  value  as  an 
instrument  to  simplify  and  demonstrate  Ohm’s  Law,  Three  Wire  System  of  Connection,  Voltage  Drop,  Efficiency 
of  Various  Types  of  Lamps  and  other  allied  subjects. 


94-350  UNIVERSAL  RESISTANCE  FRAME,  complete  with  Sockets  and  Lamps  giving  ampere  strengths 

from  0.2  to  6  amperes . $11.00 

94-363  - ,  complete  with  Resistance  Units  giving  ampere  strengths  from  0.2  to  7.2  amperes  by  0.6  ampere 

steps . 18.50 

94-366  - ,  complete  with  Resistance  Units  giving  ampere  strengths  from  0.2  to  18  amperes  by  0.6  ampere 

steps . 26.50 

94-368  - ,  complete  with  Resistance  Units  giving  ampere  strengths  from  0.2  to  40.5  amperes  by  0.6  ampere 

steps . 42.26 

94-360  MOUNTED  D.  P.  D.  T.  KNIFE  SWITCH,  —  capacity  50  amperes  at  250  volts.  Slate  base  mounted 

on  heavy  slate  sub-base .  2.75 

94-366  RIGID  ARM  PORCELAIN  MOUNTED  SOCKET  for  holding  lamps,  bridge  and  fuse  plugs.  Each  .76 

Six  4.00 

94-375  HARCOURT  RESISTANCE  UNIT,  —  6  inches  long,  0.6  ampere  capacity .  1.60 

94-376  - ,  8  inches  long,  1.2  amperes  capacity .  2.00 

94-377  - ,  10  inches  long,  2.5  amperes  capacity .  2.76 

94-378  - ,  12  inches  long,  5  amperes  capacity .  3.26 

94-380  FUSE  PLUG,  EDISON  BASE,  carrying  capacity  3  amperes . 10 

94-386  SPECIAL  BRIDGE  PLUG . 60 

Note.  —  We  should  be  pleased  to  send  a  special  descriptive  circular  showing  by  diagrams  many 
profitable  experiments. 

94-390  LAMP  BOARD,  with  32  C.  P.  LAMPS,  after  Fuller  and  Brownlee  (Experiment  77) .  9.80 


364 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


RHEOSTATS 

This  type  of  Rheostat  comprises  a  layer  of  high  resistance  wire  wound  on  an  insulating  fire-proof  slab  mounted 
on  a  polished  wooden  base  with  asbestos  shield.  They^are  fitted  with  suitable  slider  and  binding  posts  for  connecting 
in  the  circuit.  Their  open  construction  commendsjthem  for  general  laboratory  work. 

In  selecting  a  Rheostat  make  sure  that  the  ampere  capacity  is  ample  to  meet  the  requirements. 


BATTERY  RHEOSTATS.  The  following  capacities  of  the  simple  type  instrument  illustrated  under  No.  94-405 
will  be  found  well  suited  to  battery  or  other  low  voltage  circuits,  or  for  use  in  connection  with  apparatus  that  consumes 
a  large  proportion  of  the  energy  of  the  power  circuit. 


Number 

Voltage 

Maximum 

carrying 

Capacity 

Resistance 

Ohms 

Size 

Inches 

Weight 

Ounces 

Price,  Duty  Free 

94-400  A 

12 

Amperes 

7 

1.7 

4%  X  1%6  X  19/82 

10 

94-400  B 

15 

10 

1.5 

6BAe  X  l%e  X  le/s2 

14 

94-400  C 

24 

3 

8 

4%  X  1%6  X  19/82 

10 

::::  | 

94-400 D 

25 

10 

2.5 

8  X  2  X  Vi 

42 

SIMPLE  RHEOSTATS, 

especially  adapted  to  power  circuits. 

Number 

Voltage 

Maximum 

carrying 

Capacity 

Resistance 

Ohms 

Size 

Inches 

Weight 

Ounces 

Price,  Duty  Free 

94-406  A 

800 

Amperes 

.3 

2400 

18  X2^X  1 Vs 

137 

94-406 B 

112 

.3 

250 

4 %  X  l3/l6  X  19/82 

10 

.... 

94—406  C 

110 

1 

110 

6r/lfl  X  1%6  X  1%2 

14 

.... 

94-406  D 

110 

5 

22 

16  X  2  XI 

118 

.... 

DOUBLE 

RHEOSTATS, 

similar  to  the  previous  type  of  instrument,  but  comprising  two  wire-carrying  mounted 

slabs  on  a  common  base.  This  construction  enables  a 

much  larger  capacity  to  be  attained  in  a  given  space. 

Number 

Voltage 

Maximum 

carrying 

Capacity 

Resistance 

Ohms 

Size 

Inches 

Weight 

Ounces 

Price,  Duty  Free 

94-410  A 

100 

Amperes 

10 

10 

12  x  2  y8  x  1  y8 

150 

94-410  B 

110 

20 

5.5 

18  x  2Vs  X  1 Vs 

218 

.... 

94-410  C 

140 

7 

20 

12  X  2%  X  1% 

150 

.... 

94-410  D 

330 

3 

110 

12  X  2z/%  X  lVs 

150 

94-410  E 

700 

1 

700 

12  X  2%  X  1  Va 

150 

94-416  SIX-INCH  REGULATING  RHEOSTAT.  Designed  primarily  as 
a  fan  motor  speed  regulator,  this  Rheostat  has  been  modified 
for  use  as  an  adjustable  resistance.  Maximum  watt  capacity 
125.  Seven  contacts,  one  “off”  point  and  six  running  positions 
of  150  ohms  per  step.  Maximum  amperes  10. 

Mounted  on  marbleized  slate  panel  as  illustrated . $3.50 


No.  94-416 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


365 


I! 

K  RESISTANCE  UNITS 


No.  94-420 


No.  94-425 


No.  94-430 


No.  94-436 


RESISTANCE  UNITS,  approximate  dimensions  %  X  4  inches. 


50  Watts  Continuous  Duty 


Number 

Maximum 

Amperes 

Resistance 

Ohms 

Duty  Free,  Price 

Number 

94-420  a 

0.45 

250 

94-420  h 

-  b 

0.6 

125 

-  i 

-  c 

0.8 

75 

j 

-  d 

1 

45 

-  k 

-  e 

1.25 

32 

-  1 

-  f 

1.7 

16 

-  m 

-  g 

2.3 

9 

-  n 

;  RESISTANCE  UNITS,  approximate  dimensions  l}/%  X  4 %  inches. 

86  Watts  Continuous  Duty 


Maximum 

Resistance 

Number 

Amperes 

Ohms 

Duty  Free,  Price 

Number 

94-425  a 

0.45 

420 

94-425  h 

-  b 

0.6 

220 

-  i 

-  c 

0.8 

140 

-  j 

-  d 

1.0 

85 

-  k 

-  e 

1.2 

60 

-  1 

-  f 

1.6 

32 

-  m 

-  g 

2.2 

18 

-  n 

RESISTANCE  UNITS,  approximate  dimensions  l5Ao  X  6}4  inches. 

150  Watts  Continuous  Duty 


Number 

Maximum 

Amperes 

Resistance 

Ohms 

Duty  Free,  Price 

Number 

94-430  a 

0.45 

800 

94-430  h 

-  b 

0.6 

450 

-  i 

-  c 

0.8 

240 

—  j 

-  d 

1 

150 

-  k 

-  e 

1.2 

95 

1 

-  f 

1.6 

54 

-  m 

-  g 

2.2 

32 

-  n 

RESISTANCE  UNITS,  approximate  dimensions  1^  X  7 18/ia  inches. 

200  Watts  Continuous  Duty 


Number 

Maximum 

Amperes 

Resistance 

Ohms 

Duty  Free,  Price 

N  umber 

94-436  a 

0.45 

1100 

94-435  h 

-  b 

0.6 

560 

-  i 

-  c 

0.8 

320 

j 

-  d 

1 

200 

k 

- -  e 

1.2 

140 

1 

—  f 

1.6 

72 

-  m 

—  g 

2.1 

45 

-  n 

Maximum 

Resistance 

Amperes 

Ohms 

3.3 

4.5 

3.6 

3.9 

5 

2 

6.4 

1.2 

9 

0.6 

12 

0.35 

14 

0.25 

Maximum 

Resistance 

Amperes 

Ohms 

2.8 

11 

3.2 

8 

5 

3.5 

6.2 

2.2 

8.5 

1.1 

11.5 

0.65 

14.4 

0.4 

Maximum 

Resistance 

Amperes 

Ohms 

2.8 

20 

3.2 

13 

5 

6 

6.5 

3.5 

8.5 

2 

12 

1 

14 

0.8 

Maximum 

Resistance 

Amperes 

Onms 

2.8 

27 

3.2 

18 

4.7 

9 

6.3 

5 

8.5 

2.8 

11.5 

1.5 

13 

1.2 

Duty  Free.  Price 


Duty  Free,  Price 


Duty  Free,  Price 


Duty  Free,  Price 


Nos.  94-420  to  94-435  not  furnished  from  stock.  Imported  Free  of  Duty  only  when  ten  or  more  are  ordered. 


94-440  GRAPHITE  HIGH  RESISTANCE.  This  resistance  will 
be  found  of  great  convenience  in  experimental  and  test¬ 
ing  work.  Its  low  price  and  excellent  appearance  recom¬ 
mend  it  for  many  purposes.  Resistance  is  mounted  on 
polished  wood  base  provided  with  binding  posts  for  con¬ 
nections.  Capacity  1,000,000  ohms;  size  of  cylinder  4J4 
X  1%  inches . 


94-442 


•,  same  as  above,  but  100,000  ohms  . 


No.  94—442 


366 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


WHEATSTONE  BRIDGES 

DEMONSTRATION  WHEATSTONE  BRIDGES 


Too  little  attention  has  been  given  in  schools  to  a  thorough  understanding  of  that  basic  principle,  Fall  of  Po¬ 
tential,  fundamental  to  Wheatstone  Bridge  work.  A  student’s  incomplete  understanding  of  Fall  of  Potential  makes 
it  difficult  for  him  to  understand  what  he  is  striving  to  obtain  when  he  uses  a  Wheatstone’s  Bridge.  This  incom¬ 
plete  understanding  is  due,  perhaps,  to  the  word  of  mouth  descriptions  and  the  lack  of  adequate  illustrative  demon¬ 
strative  apparatus.  To  picture  for  him  the  actual  Fall  of  Potential,  we  heartily  recommend  the  following  apparatus. 
The  analogy  between  hydraulic  pressure  and  electromotive  force  is  often  resorted  to  by  teachers,  yet  the  analogy 
has  never  been  worked  out  instrumentally  except  in  the  following  apparatus. 


No.  94-455 


94-455  HYDRODYNAMIC  WHEATSTONE  BRIDGE  for  a  study  of  the  principles  involved  by  measure¬ 
ments  of  resistances  by  the  Wheatstone’s  Bridge  method,  using  Fall  of  Hydraulic  Pressure  as  an 
analogy  to  electromotive  force.  On  a  polished  wooden  base  board  is  mounted  a  system  of  tubes  con¬ 
nected  to  form  a  Wheatstone’s  diagram.  In  the  “arms”  are  reducing  valves  analogous  to  resis¬ 
tances.  Pressures  in  the  various  arms  are  indicated  by  the  manometers.  In  the  “bridge”  is  a 
pressure  indicator  analogous  to  the  galvanometer. 

By  connecting  to  one  of  the  nipples  noted  in  the  illustration  and  allowing  a  flow  of  water  through 
the  apparatus,  the  fall  of  pressure  through  the  different  arms  may  readily  be  noted.  By  regulating 
the  reducing  valves  in  these  arms,  a  balance  may  be  secured  when  no  indications  of  pressure  can  be 
noted  in  the  “bridge.”  The  pressures  in  the  arms  will  then  be  noted  in  the  manometer. 

The  didactic  value  of  this  apparatus  will  readily  be  noted.  The  construction  is  substantial,  results 
possible  are  positive,  parts  are  carefully  fitted  and  handsomely  finished. 

Complete  as  illustrated . $34.50 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


367 


No.  94-460 


94-460  DEMONSTRATION  WHEATSTONE  BRIDGE  for  a  study  of  Fall  of  Potential  and  demonstration 
of  the  principle  of  a  Wheatstone  Bridge. 

This  apparatus  consists  of  a  vertically-mounted  board  to  which  is  attached  the  Wheatstone  Diagram. 
In  the  “arms”  are  connected  incandescent  lamps.  In  the  “bridge”  an  indicating  galvanometer. 
Binding  posts  are  provided  for  connecting  resistances  in  shunt  with  the  lamp.  By  varying  the  re¬ 
sistances  a  point  of  same  potential  may  be  secured. 

As  a  companion  instrument  to  No.  94-466  Hydrodynamic  Wheatstone  Bridge,  demonstrations  of 
Fall  of  Potential  as  utilized  in  the  Wheatstone  Bridge  are  simply  and  clearly  made. 

Complete  as  illustrated  with  incandescent  lamps . 


No.  94-470 


94-470  WORKING  DEMONSTRATION  WHEATSTONE  BRIDGE,  DIAMOND  FORM.  The  merit  of  a 
Wheatstone  Bridge  that  may  be  used  equally  as  well  in  demonstration  as  in  laboratory  practise 
will  at  once  be  recognized. 

The  instrument  illustrated  is  constructed  so  that  the  arms  are  arranged  as  the  Wheatstone  Diagram. 
In  addition  in  each  of  the  “ratio  arms”  are  coils  of  1,  10,  and  100  ohms.  The  “balance  arms”  are 
provided  with  gaps  each  with  non-detachable  binding  posts,  one  pair  for  the  known  and  the  other 
pair  for  the  unknown  resistance.  Non-detachable  binding  posts  and  key  are  provided  for  battery 
and  galvanometer  circuits.  All  parts  of  this  instrument  are  well  made.  They  are  carefully  fitted 
and  the  instrument  is  guaranteed  to  give  good  satisfaction . 


$26.00 


$6.80 


368 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


SLIDE  WIRE  WHEATSTONE  BRIDGES 


No.  94-480 

94-480  WHEATSTONE’S  STANDARD  METER  SLIDE  WIRE  BRIDGE.  In  this  design,  especially 

adapted  for  students’  laboratory  experiments,  we  furnish  an  excellent  bridge  at  a  reasonable  price. 
Heavy  copper  leads,  non-detachable  binding  posts,  Inanganin  wire,  improved  positive  sliding  con¬ 


tact  key,  mounted  on  polished  hardwood  base . . $3.35 

94-482  WHEATSTONE’S  BRIDGE,  after  Millikan  and  Gale’s  “A  Laboratory  Course  in  Physics”  (Ex¬ 
periments  32  and  33) .  2.00 


No.  94-490 

94-4901WHEATSTONE’S  HALF  METER  BRIDGE,  HARCOURT  FORM.  This  bridge  is  in  construction 

similar  to  No.  94-480,  and  in  quality  fully  its  equal. 

To  economize  space  as  well  as  facilitate  its  use,  it  is  made  in  half  meter  length,  but  so  designed  as  to 
carry  the  full  meter  length  of  wire.  In  accuracy,  therefore,  it  compares  favorably  with  the  full- 
length  bridge . • . $2.80 


No.  94-495 

94-495  HALF  METER  WHEATSTONE-CAREY-FOSTER  BRIDGE.  Extra  heavy  brass  strips,  non- 

detachable  binding  posts,  improved  sliding  knife-edge  contact  key,  improved  scale  mounted  on 
highly  polished  base . $9.00 


No.  94-500 

94-500  COWEN  COMBINATION  BRIDGE.  This  Bridge  was  first  constructed  for  the  Boston  High  Schools, 
but  is  now  generally  recognized  as  a  Wheatstone  Bridge  having  unusually  valuable  educational 
features. 

It  is  provided  with  an  especially  designed  resistance  box  set  in  the  base,  and  furnished  as  a  part  of 
the  instrument.  A  horizontal  D’Arsonval  Galvanometer  No.  93-196  is  also  mounted  on  the  base. 
Thus  it  may  be  seen  that  a  complete  measuring  unit  combining  bridge,  resistance  box,  and  galva¬ 
nometer  is  furnished  as  a  unit  system.  The  necessity,  therefore,  of  all  outside  connections  except 
those  from  the  battery  and  unknown  resistance  is  entirely  avoided.  The  permanent  connections 
to  the  resistance  box  and  the  galvanometer  are  made  on  top  of  the  bridge  in  such  form  that  the 


direction  of  the  current  can  be  most  easily  traced. 

Combination  Bridge,  Box,  and  Galvanometer . $22.60 

94-602  COWEN  COMBINATION  BRIDGE  and  Box  without  Galvanometer . 16.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


369 


No.  94^625 

94-525  THE  UNIVERSITY  SLIDE  WIRE  BRIDGE,  adapted  for  measuring  resistances  with  low  E.  M.  F. 

where  the  plug  form  of  Resistance  Box  would  be  useless.  Provided  with  both  mercury  cup  and 
binding  post  contact,  the  Lattimer-Clark  Commutator,  tension  spiral  for  bridge  wire,  contact  with 
rack  and  pinion  and  fine  adjustment,  locking  device  for  holding  the  contact  at  any  desired  point. 

Connecting  bars  of  large  cross  section,  tested  for  uniform  density.  Mercury  cups  of  ]/i  inch  diam¬ 
eter  with  bottom  finished  to  give  perfect  contact. 

Binding  posts  of  large  size,  provided  for  each  gap  in  addition  to  the  mercury  cup. 

Four  gaps  are  provided  for  ratio  coils  and  extension  coils,  which  are  also  available  for  inserting  coils 
in  the  conventional  Wheatstone  Bridge  arrangement.  The  commutator  may  be  removed,  leav¬ 
ing  available  two  extra  gaps  which  may  be  required  in  special  work. 

Spring  Tension  insures  uniform  tension  on  the  resistance  wire.  Wire  supplied  for  this  work  will 
be  manganin  unless  otherwise  specified. 

Slider.  Combination  Rack  and  Pinion  and  fine  adjustment  with  push  button  locking  device,  makes 
a  most  satisfactory  method  of  obtaining  a  sliding  contact.  The  contact-is  entirely  enclosed  to 
overcome  any  possible  thermo-electric  disturbance  due  to  the  presence  of  the  hand  of  the  operator. 

The  scale  is  engine-divided  with  vernier  reading  to  tenths  of  a  millimeter. 

Base  is  of  three-ply  mahogany  to  prevent  warping,  oil  finished. 

An  instrument  of  the  highest  accuracy  and  convenience,  substantially  and  beautifully  finished  .  .  $75.00 


No.  S4-6S6 


94-535  THE  UNIVERSAL  CAREY-FOSTER  BRIDGE.  The  Carey-Foster  method  is  recognized  as  the 
one  suited  to  the  most  rapid  and  accurate  work  in  electrical  measurements.  It  is,  in  fact,  the 
method  which  we  have  found  in  our  own  testing  department  to  give  not  only  the  most  reliable 
results,  but  one  which  permits  the  largest  number  of  measurements  per  unit  of  time. 

The  Bridge  above  illustrated  is  substantially  the  one  used  in  our  own  electrical  measurements,  and  is 
therefore  adapted  to  a  very  wide  range.  The  low  resistance  swinging  arms,  the  mercury  contacts, 
the  sliding  bridge,  the  essential  features  of  which  are  made  substantially  as  in  instrument  No.  94- 
526,  the  micrometer  movement  on  the  contact,  the  heavy  insulated  low  resistance  copper  leads,  the 
Carey-Foster  reversing  key,  combine  to  give  this  instrument  a  place  in  high-grade  electrical  meas¬ 
urements  not  filled  by  any  other  form.  ,  .  .  .  ,  , 

The  accuracy  with  which  this  Bridge  is  made  will  perhaps  be  appreciated  when  it  is  known  that  even 
the  J^-inch  copper  lead  wires  and  the  heavy  copper  buss  bars  are  carefully  tested  and  adjusted 

•  before  being  set  up  in  the  instrument.  .  .  .  .  .  .  .  . 

The  bases  are  made  of  three-ply  mahogany  finished  in  oil;  the  finish  on  the  entire  instrument  is  in 
keeping  with  that  of  a  thoroughly  high-grade,  accurate,  scientific  instrument . 


370 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


TRANSFORMING  AND  INTERRUPTIVE 

APPARATUS 


95-10  FARADAY’S  RING  AND  DEMONSTRATION  TRANSFORMER.  This  simple  apparatus  is  de¬ 
signed  for  study  of  the  principles  and  laws  involved  in  self  and  secondary  induction;  also  the  appli¬ 
cations  of  these  laws  to  the  step-up  and  step-down  transformer. 

It  consists  of  a  closed  magnetic  circuit  within  a  coil  of  wire  which  is  tapped  and  brought  to  binding 
posts,  dividing  itself  into  four  coils  of  an  equal  number  of  turns.  The  ring  and  binding  posts  are 
mounted  on  a  neatly  finished,  polished  base,  making  a  compact,  well  worked  out  instrument  in  which 
the  ratios  of  transformation  on  a  unit  of  voltage  are  as  follows:  — 

1:1;  1:2;  1:3;  1:4;  2:1;  2:3;  3:2;  3:1;  4:1 . . 

95-16  INDUCTION  COIL,  after  Millikan,  Gale  &  Bishop,  Exp.  36. 

This  is  a  simple  coil  of  wire  wound  on  a  brass  spool . Each 


No.  95-10 


$3.25 


92-110  GILLEY  INDUCTION  COILS,  Figs.  1  and  6,  mounted  with  binding  posts.  These  coils  are  described 

on  page  330  and  are  recommended  for  general  experiments  in  Induction  ....  Per  set  of  two  $1.40 


92-115  SOFT  IRON  U-SHAPED  CORE,  Figure  3,  for  study  of  bi-polar  electro  magnets . Each  .20 

92-117  SOFT  IRON  ARMATURE,  Figure  2,  for  use  with  the  above  core  in  the  study  of  electro-magnets. 

Each  .10 

92-120  SOFT  IRON  CORE,  Figure  6,  single,  for  the  study  of  electro-magnets  . Each  .10 

92-122  PAIR  OF  HALF-ROUND  CORE  PIECES,  Figure  4,  for  mapping  the  lines  of  force  in  an  electro¬ 
magnet . Per  pair  .16 

92-125  PAIR  OF  SLOTTED  CARDBOARDS,  Figure  7,  for  mapping  lines  of  force  . Per  pair  .08 

92-130  COMPLETE  GILLEY  INDUCTION  OUTFIT,  supplied  in  box  with  direction  sheets .  2.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


371 


No.  95-30 

THE  IMPROVED  EDUCATIONAL 
DISSECTIBLE  TRANSFORMER 

ANY  VOLTAGE  UP  TO  115 


Patent  Pending 

In  the  designing  of  this  Transformer  we  have  had  in  mind  an  instrument  resembling  as  closely  as  possible 
the  commercial  instrument.  In  order  to  make  it  of  the  greatest  practical  use  in  the  laboratory  and  at  the 
same  time  serve  to  teach  all  of  the  fundamental  forms  of  Transformers,  the  dissectible  feature  is,  of  course, 
essential,  since  a  school  can  hardly  afford  to  buy  as  many  different  Transformers  as  there  are  types  in  com¬ 
mercial  use. 

The  instrument  which  we  have  produced  will  be  found  of  the  greatest  use  in  demonstrating  the  principles 
and  laws  involved  in  self  and  secondary  induction,  also  the  application  in  commercial  work  of  the  step-up  and 
step-down  transformer. 

.  CONSTRUCTION.  In  form  and  in  methods  of  construction,  the  regular  commercial  instrument  as  used 
in  lighting  and  power  systems  has  been  followed:  —  laminated  core,  taped  coil,  every  feature  designed  to  give 
the  greatest  efficiency  and  greatest  durability. 

The  dissectible  feature,  which  enables  the  student  to  take  the  instrument  apart,  examine  and  test  each 
part  separately,  i$  obtained  as  follows :  — 

The  core  is  of  punchings  made  from  the  best  electrical  sheet  iron,  punchings  arranged  in  groups  of  ten, 
each  group  being  held  together  by  riveting,  for  convenience  in  assembling.  Primary  coils  are  taped^and  sup¬ 
plied  with  convenient  leads.  Secondary  coils  are  taped  and  supplied  with  leads.  These  features  enable  the 
instrument  to  be  assembled  either  as  a  Faraday  Ring,  Auto  Transformer  of  the  shell  type,  an  Auto  Trans¬ 
former  of  the  block  or  iron-clad  type,  a  Primary  and  Secondary  Transformer  of  the  shell  type,  a  Primary  and 
Secondary  Transformer  of  the  block  type. 

RANGES  IN  VOLTAGE.  The  ratios  of  the  primary  to  the  secondary  coils  are  such  that  a  great  variety  of 
transformations  may  be  had.  If  the  primary  circuit  is  110  volts,  the  voltages  drawn  from  the  secondary  in 
various  combinations  (fully  illustrated  by  diagrams  furnished  with  each  instrument)  are  7,  15,  30,  60,  220,  235, 
and  255  volts.  Other  ranges  may  be  obtained  by  using  a  different  voltage  in  the  primary  line,  the  ratios  of 
transformation  in  each  case  being  as  above  indicated. 

For  convenience  in  use  the  instrument  is  mounted  on  a  mahogany  base  with  six  double  binding  posts  as 
illustrated. 

The  instrument  serves  to  teach  effectively:  — 

1.  The  influence  of  iron  in  the  core.  6.  Back  electro-motive  force,  and  many  other  funda- 

2.  The  magnetic  hysteresis.  mental  principles  in  alternating  current  practice 

3.  Eddy  Currents.  not  possible  with  any  instrument  heretofore  offered. 

4.  Magnetic  density.  Full  directions  with  descriptive  diagrams  will  be 

5.  Self-Induction.  supplied  with  each  transformer. 

Complete  with  full  equipment  for  teaching  all  of  the  points  above  mentioned . $11225 

Note:  We  should  be  pleased  to  send  a  special  descriptive  circular  showing  by  diagrams  many  profitable 
experiments. 


372 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PRIMARY  AND  SECONDARY  COILS 

96-38  STUDENTS’  PRIMARY  AND  SECONDARY  COIL.  Height  7 inches.  Consists  of  two  hardwood 
spools,  the  outer  one  provided  with  a  base,  and  the  inner  one  removable.  The  inner  spool  is 
wound  with  a  few  turns  of  coarse  wire  and  is  the  “primary,”  the  outer  with  many  turns  of  fine 
wire  and  is  the  “secondary.” 

Complete  with  soft  iron  core . $3.30 


t 


96-40  LARGE  PRIMARY  AND 
SECONDARY  COLL,  for 
the  study  of  current  in¬ 
duction.  This  form,  with 
its  primary  6  inches 
by  inches  and  its 

secondary  2 ]A  inches  by 
5  inches,  must  not  be 
confused  with  the 
smaller  types  on  the 
market.  We  have  de¬ 
sired  in  this  instrument 
to  offer  the  teacher  an 
instrument  capable  o  f 
efficient  positive  results. 
This  can  be  secured  in  a 
satisfactory  manner  only 
by  using  a  large  number 
of  windings  on  the  sec¬ 
ondary  circuit.'  The 
wire  in  each  circuit  is 
mounted  o  n  separate 
hardwood  spools,  and  the 
secondary  is  mounted  on 
a  neatly  polished  hard¬ 
wood  base.  To  insure 
greater  rigidity  we  have 
added  two  brass  rods 
connecting  the  secondary 
to  the  base  (see  illustra- 
,  tion  below).  The  wire 
used  is  silk  covered,  and 

binding  posts  are  neatly  polished  and  lacquered.  The  soft  iron  core  supplied  with  the  instrument 
consists  of  a  bundle  of  soft  iron  wires  tightly  moulded  by  bands  to  form  a  nearly  solid  rod. 
Primary  and  Secondary  Coil  complete  with  iron  core . . 


No.  95-40 


$7.50 


96-45  LARGE  PRIMARY  AND  SEC¬ 
ONDARY  COIL,  similar  to 
above,  but  provided  with  vi¬ 
brator  mounted  on  same  base 
with  coil.  This  vibrator  is  of 
the  simple  electromagnetic  type 
and  gives  positive  interruptions 
to  the  current,  illustrating  the 
simple  induction  coil.  This  in¬ 
strument  is  of  substantial  con¬ 
struction,  and  all  parts  are  finely 
polished  and  finished. 

Complete  as  illustrated . $10.50 

96-50  MAKE  AND  BREAK  INTER¬ 
RUPTER.  It  is  frequently  de¬ 
sired  to  attach  a  Make  and 
Break  Interrupter  to  an  un¬ 
mounted  primary  and  second¬ 
ary  coil.  The  type  which  we 
furnish  is  the  same  as  illus¬ 
trated  on  the  base  of  the  Pri¬ 
mary  and  Secondary  Coil  No. 

96-46. 

The  parts  are  mounted  on  a  neat 
wooden  base  ready  for  attach¬ 
ment  to  the  terminals  of  the 
secondary .  3.00 

INTERRUPTING  WHEEL.  See  No.  90-460. 


No.  96-45 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


373 


INDUCTION  COILS 


Nos.  95-75  to  96-80  No.  95-96 

96-76  DEMONSTRATION  INDUCTION  COIL.  This  type  of  coil  is  of  value  in  the  study  of  the  office  of 
the  primary  in  induction  coil  construction.  Both  primary  and  secondary  are  mounted  on  a  pol¬ 
ished  mahogany  box,  but  the  mounting  is  designed  so  that  the  secondary  maybe  adjusted  to  enclose 
varying  amounts  of  the  primary. 

This  instrument  is  handsomely  finished,  all  brass  parts  polished  and  lacquered,  and  will  give  a 

X-inch  spark . $6.00 

96-80  - ,  same  as  above,  but  calculated  to  give  a  >^-inch  spark .  8.26 

96-95  DEMONSTRATION  DISSECTIBLE  RUHMKORFF  COIL.  This  coil  is  constructed  so  that  all  es¬ 
sential  details  of  a  commercial  Ruhmkorff  coil  may  be  shown  as  units  and  in  their  relations  to  the 
rest  of  the  instrument.  Thus  the  condenser  is  mounted  in  a  drawer  slide.  Connections  with  the 
secondary  are  secured  through  binding  posts.  The  primary  may  be  dissected  and  taken  from  the 
instrument.  The  make  and  break  and  core  are  of  special  design  calculated  to  teach  the  principle, 
and  all  connections  are  fully  in  the  open  and  may  readily  be  noted  at  a  glance . 37.50 


RUHMKORFF  COILS 


Nos.  96-126  to  96-140 

Our  small  types  of  Ruhmkorff  Coils  up  to  1-inch  spark  are  construced  for  us  by  a  prominent  European  manu¬ 
facturer.  They  are  of  standard  quality  designed  for  elementary  work. 

Ruhmkorff  Coils  with  a  capacity  of  two  inches  (see  next  page)  are  constructed  by  us  in  our  own  factory.  We 
are,  therefore,  enabled  to  furnish  a  product  superior  in  quality  to  that  ordinarily  furnished  of  European  make.  We 
secure  a  greater  efficiency  and  are  enabled  to  place  in  the  hands  of  the  buyer  a  more  finished  instrument.  The  parts 
of  these  coils  are  of  the  best  proportions  to  give  the  maximum  efficiency  and  preserve  symmetry.  Only  the  best 
quality  of  material  is  used  in  construction,  and  all  parts  are  handsomely  finished. 

We  are  enabled  to  guarantee  our  coils  up  to  their  full  capacity  and  warrant  them  against  faulty  construction. 

EUROPEAN  COILS 

96-125  RUHMKORFF  COIL,  capacity  %-inch  spark . $4.26 

96-130  - ,  capacityX-inch  spark .  £.90 

96-135  - ,  capacity  j^-inch  spark . 

96-140  - ,  capacity  1-inch  spark  . 21.00 


374 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


THE  “NEW  LINE”  INDUCTION  COILS 


Nos.  95-175  to  95-210 


Because  of  the  great  improvements  in  Induction  Coil  design  during  the  past  three  years,  it  is  with  especial  pleas¬ 
ure  that  we  call  your  attention  to  our  series,  ranging  from  2  to  18-inch  discharge. 

These  coils  are  construced  according  to  the  latest  and  best  high-tension  data.  The  rigorous  demands  of 
X-Ray  and  Wireless  work  have  rendered  valueless  coils  constructed  according  to  formulae  previously  used. 

The  entire  construction  of  the  coil  is  based  on  the  requirements  of  heavy  discharge  rather  than  length  of  spark. 
This  is  obtained  by  the  use  of  exceptionally  heavy  primaries  with,  of  course,  the  best  possible  insulation.  Every 
feature  has  been  worked  out  with  the  greatest  care  looking  towards  the  building  of  a  coil  which  cannot  be  broken 
down  and  which  will  give  the  desired  results  on  comparatively  low  battery  power,  and  in  coils  designed  for  use  on 
110-volt  current  which  wall  take  the  rated  voltage  and  amperage  without  danger. 

TESTING.  Each  coil  is  subjected  to  a  rigorous  test  with  an  overload  of  100%  to  insure  against  breaking  down 
with  ordinary  usage.  , 

96-176  £  NEW  LINE  INDUCTION  COIL,  guaranteed  discharge  2  inches 


95- 180 

96- 185 

95- 190 

96- 196 
96-200 
96-205 
96-210 


same  as  above,  guaranteed  discharge  4  inches 
guaranteed  discharge  6  inches  . 
guaranteed  discharge  8  inches  . 
guaranteed  discharge  10  inches 
guaranteed  discharge  12  inches 
guaranteed  discharge  16  inches 
guaranteed  discharge  18  inches 


$37.60 

66.00 

76.00 

100.00 

120.00 

146.00 

200.00 

240.00 


No.  96-230 


LIQUID  INTERRUPTING  INDUCTION  COIL,  for  a  110-volt  current.  In  connection  with  our  “New  Line” 
Induction  Coils  above  listed  we  have  worked  out  an  instrument  for  use  on  the  110-volt  current,  especially  designed 
to  withstand  the  entire  current  from  Liquid  Interrupter  No.  96-262.  It  gives  a  heavy  discharge,  admirably  suited 
for  Wireless,  X-Ray,  and  general  induction  coil  experiments.  It  may  be  used  with  safety,  as  these  coils  are  de¬ 
signed  not  to  burn  out  on  a  110- volt  current. 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


375 


The  7-inch  discharge  which  these  coils  are  designed  to  give  is  such  as  is  found  most  satisfactoryjfor  general  all¬ 


round  work  in  X-Ray  and  Wireless  experiments. 

96-225  LIQUID  INTERRUPTING  INDUCTION  COIL,  complete  with  Liquid  Interrupter . $73.80 

96-230  - ,  same  as  above,  without  Interrupter  . 60.00 


We  are  listing  both  coil  and  interrupter  together  for  the  reason  that  it  is  somewhat  easier  to  adjust  the  inter¬ 
rupter  to  the  coil  if  both  are  ordered  at  one  time.  This  adjustment,  however,  is  not  absolutely  necessary  as  a  care¬ 
ful  record  is  made  of  each  coil  and  the  adjustment  can  be  made  at  a  later  date. 


THE  ELECTROLYTIC  INTERRUPTER 


Nos.  96-250  to  96-252 

Patents  Pending 


The  difficulty  with  Electrolytic  Breaks  heretofore  used  has  arisen  largely  because  of  the  failure  of  the  manu¬ 
facturers  to  adjust  the  size  of  the  gas  tube  to  the  line  voltage  and  the  amperage  which  is  to  be  drawn  from  the  break. 
This  difficulty  has  been  fully  recognized  and  satisfactorily  met. 

We  can  supply  our  new  design  of  Electrolytic  Interrupter  for  any  voltage  and  amperage  desired.  The  two 
forms  selected  as  being  most  generally  serviceable  are  listed  below  and  are  rated  according  to  the  Induction  Coil 
capacity  with  which  they  are  to  be  used.  Please  note  that  they  will  operate  on  a  direct  or  alternating  current. 

CONSTRUCTION.  Our  Interrupter  contains  a  porcelain  cylinder  in  which  the  size  of  the  opening  is  carefully 
adjusted  to  the  amperage  of  the  current  to  be  drawn.  In  order  to  avoid  breakage  this  cylinder  is  carried  on  a  lead 
shelf,  being  part  of  the  inner  lead  cylinder. 

The  terminals,  as  will  be  noted  in  the  cut,  are  carried  well  out  on  the  ends  of  the  long  lead  bars,  bent  over  and 
beyond  the  top  of  the  instrument  so  as  to  reduce  the  objectionable  corrosion  that  is  unavoidable  when  the  terminals 
are  above  the  jar  and  subjected  to  the  action  of  the  acid  fumes  thrown  off  when  the  Interrupter  is  in  operation. 

METHOD  OF  COOLING.  A  substantial  iron  receptacle  is  provided  which  acts  as  a  radiator  and  serves  to 
keep  the  liquid  from  overheating.  This  receptacle  also  serves  to  protect  the  table,  floor,  or  other  apparatus  in  case 


of  accidental  breaking  of  the  acid  jar. 

96-260  ELECTROLYTIC  INTERRUPTER,  type  A,  for  coils  from  4  to  6-inch  spark . $13.80 

96-262  ELECTROLYTIC  INTERRUPTER,  type  B,  for  coils  form  7  to  12-inch  spark  . 13.80 


376 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ELECTRO-DYNAMIC  APPARATUS  FOR 
ALTERNATING  CURRENTS 


95-260  ELECTRO-DYNAMIC  APPARATUS.  This  apparatus  has  been  designed  for  the  purpose  of  showing 
the  repulsion  and  rotation  effects  produced  by  an  alternating  current.  It  is  designed  to  operate  on 
a  commercial  circuit  of  110  volts,  the  alternating  current  being  recommended.  It  may  be  used, 
however,  satisfactorily  on  the  direct  current  if  used  in  connection  with  our  Electrolytic  Interrupter 
No.  96-262.  The  apparatus  is  complete,  covering  a  full  set  of  parts  for  performing  a  most  instruc¬ 
tive  series  of  experiments.  A  few  of  these  we  note  herewith:  — 

Diaphragm  made  to  vibrate  in  unison  with  the  alternations  of  the  current  so  as  to  give  out  a 
distinct  tone. 

Repulsion  of  a  copper  disc  held  in  proximity  to  the  iron  core  on  the  balance  arm. 

The  rotation  of  the  copper  disc,  caused  by  the  revolving  field. 

The  rotating  ball.  A  copper  ball,  placed  over  the  exposed  end  of  the  iron  core  and  one-half  of 
the  core  covered  with  a  copper  disc,  will  rotate.  By  floating  the  ball  in  a  jar  of  water, 
the  rotation  becomes  rapid. 

Lighting  of  an  electric  lamp  by  means  of  the  pulsations  given  out  from  the  iron  core,  this  be¬ 
ing  accomplished  through  the  glass  jar. 

The  suspension  of  a  heavy  metal  ring  placed  around  the  iron  core. 

The  comparative  repulsion  of  copper  and  aluminum  rings. 

Heating  effect  in  a  copper  ring,  shown  by  the  boiling  of  a  liquid. 

These  and  many  other  experiments  may  be  performed  with  the  above  apparatus.  Their  strik¬ 
ing  character  has  caused  the  outfit  to  be  extensively  used  as  a  lecture  table  set. 

Complete  directions  for  operating  and  performing  many  experiments  are  furnished  with  the  outfit. 

$56.00 


i 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


377 


1 


95-300 


OZONE  GENERATOR  TUBE,  a  simple  glass  therapeutical  device  known 
as  an  Ozone  Generator  Tube.  This  instrument  has  been  listed,  as  it  has 
several  features  of  educational  value.  In  operation  the  central  ter¬ 
minal  is  connected  to  a  source  of  High  Frequency  Current  which  will 
fill  the  air  chamber  surrounding  the  central  vacuum  tube  with  a  fine 
brush  discharge,  instantly  transforming  a  portion  of  the  Oxygen  of  the 
air  into  Ozone,  which  is  readily  detected  by  the  odor.  If  desired,  Oil  of 
Pine,  Starch  Solution,  or  similar  Ozone '  detecting  chemicals  may  be 
placed  in  the  upper  chamber  of  the  device  and  the  air  forced  through 
them  by  simply  pressing  the  bulb  furnished.  The  instrument  being 
made  entirely  of  glass,  all  operations  are  clearly  visible  . 


$12.50 


No.  95-310 


95-310  SEPARATELY  MOUNTED  RESONANT  LEYDEN  JARS,  a  pair  of  jars  mounted  on  independent 
stands,  each  being  fitted  with  an  adjustable  discharging  circuit,  for  demonstration  of:  — 

I.  Resonance  between  Electrical  Circuits. 

'  2.  The  Oscillatory  Character  of  the  Condenser  Spark. 

3  Tuning  as  applied  to  so-called  High  Frequency  Circuits,  Wireless  Telegraphy,  etc. 

They  make  an  impressive  and  instructive  lecture  table  outfit.  In  operation  one  of  the  jars  should  be 
charged  by  means  of  a  static  machine  or  induction  coil,  and  at  each  discharge  a  simultaneous 
spark  will  be  obtained  from  the  other  jar  providing  that  its  loop  is  adjusted  to  the  same  positions  as 
the  loop  on  the  first.  Changing  the  size  of  the  loop  on  either  of  the  jars  without  altering  the  other 
will  throw  them  out  of  tune,  and  the  charge  on  one  will  be  much  less  than  on  the  other  When  in 
tune  the  two  parts  of  the  outfit  may  be  removed  a  considerable  distance  apart,  thus  showing  in  a 
very  clear  manner  the  wonderful  sensitiveness  of  resonsant  circuits.  , 

The  outfit  is  usually  equipped  with  one-quart  Leyden  Jars,  but  jars  either  larger  or  smaller  may  be 
used  if  at  hand,  thereby  greatly  increasing  the  educational  value  of  the  device,  for  it  can  be  shown 
that  to  obtain  resonance  the  value  of  the  condenser  times  the  inductance  or  loop  must  be  the  same, 
i.  e.,  a  large  jar  discharging  through  a  small  part  of  the  loop  of  conductor  will  energize  the  other 
or  smaller  jar  through  a  larger  part  of  its  circuit,  etc. 

Separately  Mounted  Resonant  Leyden  Jars,  complete  as  illustrated . 


378 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


HIGH  FREQUENCY 


Experimental  work  with  high  frequency  currents  has  been  impeded  by  the  lack  of  well-designed  apparatus  in 
marketable  form.  The  coils  which  are  listed  on  the  following  pages  are  the  results  of  fifteen  years’  experience  in  the 
construction  of  high  frequency  apparatus,  the  first  coil  of  this  general  type  being  built  by  us  in  the  early  days  of  high 
frequency  work.  It  has  taken  years  of  careful  study,  however,  to  learn  how  best  to  combine  the  elements  embodied 
in  these  instruments  so  as  to  produce  a  compact,  safely  handled  coil  giving  adequate  power  with  a  range  of  adapta¬ 
bility  which  would  especially  fit  it  for  a  scientific  study  of  high  frequency  phenomena. 


No.  95-325 

UNI-POLAR  HIGH  FREQUENCY  COIL 

TEN -INCH  CONTINUOUS  DISCHARGE 


No.  95-325 

This  instrument  is  a  most  striking  outfit  for  general  lecture  work  and  for  exhibition.  It  is  built  on  lines 
that  have  proven  successful  in  the  highest  grade  instrument  construction.  Not  only  does  its  peculiar  com¬ 
pact  design  protect  the  working  parts  when  not  in  use,  but  it 
also  affords  an  instrument  that  is  readily  transportable  from 
place  to  place.  Although  when  folded  it  occupies  16^4  X 
X  9%  inches,  when  open,  it  is  not  only  large,  but  all  the  vital 
parts  are  held  at  a  considerable  distance  apart,  so  that  a  very 
large  amount  of  energy  can  be  handled  without  overloading  or 
subjecting  the  various  parts  to  an  undue  strain.  The  instru¬ 
ment  is  entirely  self-contained  and  after  being  connected  to 
the  lighting  circuit  by  means  of  a  cord  and  plug,  it  is  ready  for 
use. 

We  desire  to  call  particular  attention  to  the  construction 
of  this  coil.  Its  design  has  been  the  result  of  careful  investiga¬ 
tion,  and  the  expenditure  of  a  great  amount  of  time  and  money. 

We  believe  that  there  has  been  attained  a  perfection  not 

reached  by  any  instrument  of  its  class.  It  comprises  no  new  or  untried  parts  or  material.  We  have  watched 
its  development  and  operation  for  several  years,  and  when  thoroughly  convinced  of  its  merits,  utility,  and 
“standing-up”  qualities,  made  arrangements  with  its  inventor  for  its  sale  in  educational  institutions.  We 
are  enabled  to  fully  guarantee  this  coil  against  accidental  “break-downs”  and  against  “burn-outs.” 

Designed  for  alternating  current,  complete  with  carrying  strap,  connecting  cords  and  Edison  plug,  and 
with  pamphlet  descriptive  of  care  and  use . $200. 


Showing  Coil  Folded 


00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


379 


HIGH 


No.  95-335 

FREQUENCY  INDUCTIVE 
APPARATUS 


No.  95-335 

This  instrument  represents  a  radical  departure  from  the  types  of  high  frequency  coils  pre¬ 
viously  offered.  By  combining  the  open  type  of  resonator  commonly  used  in  European  labora¬ 
tories  with  the  closed  core  type  of  transformer  and  silver  spark  gap,  unusual  efficiency  is  obtained, 
producing  an  instrument  particularly  well  adapted  to  the  study  of  alternating  and  high  frequency 

phenomena. 

Provision  has  been  made  for  varying  the  value  of  both  the  condenser  and  inductance.  Cur¬ 
rents  of  varying  frequencies  can  thus  be  produced,  enabling  comparisons  to  be  made  between  the 
effects  produced  by  changing  either  capacity  or  inductance. 

Both  the  secondary  and  the  oscillator  are  easily  removed.  Also,  the  entire  resonator  may  be 
readily  taken  off  from  the  instrument,  permitting  experimental  apparatus  to  be  attached  to  the 
low  voltage  (approximately  10,000  volts,)  high  frequency  primary  current. 

PURPOSE.  —  This  apparatus  is  designed  for  a  comprehensive  study  of  the  high  frequency 
field,  including  wireless  telegraph  waves  and  kindred  subjects.  It  may  also  be  used  with  great 
satisfaction  to  excite  all  types  of  vacuum  tubes  and  will  produce  X-Rays  of  surprising  power  and 
penetration. 

USE.  —  It  is  designed  to  be  connected  to  a  commercial  alternating  current  of  110  volts  and 
will  furnish  a  discharge  of  any  desired  value  up  to  its  full  capacity,  which  is  about  12  inches.  Its 
ease  of  control  and  great  range  of  usefulness  make  it  of  particular  value  in  general  laboratory  ex¬ 
periments  and  experiments  on  the  scientific  study  of  Electro-therapeutics. 

The  mounting  is  mahogany,  the  condenser  of  mica  and  the  secondary  oscillator  is  wound 
on  a  large  mica  tube.  The  highest  grade  material  only  is  used,  —  the  workmanship  the  best 
that  mechanical  skill  can  produce . $160.00 


38o 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


No.  95-340 

BI-POLAR  HIGH  FREQUENCY  COIL 

TWELVE-INCH  CONTINUOUS  DISCHARGE 
Designed  for  Alternating  Current 


No.  95-340 


96-340  BI-POLAR  HIGH  FREQUENCY  COIL.  This  coil  is  designed  to  furnish  a  powerful  high  frequency- 
discharge,  suitable  for  X-Ray  work  and  general  experiments  requiring  high  voltage.  It  is  of  ample 
proportions  and  entirely  self-contained.  It  is  of  the  bi-polar  type,  i.  e.,  each  terminal  is  active  and 
throws  off  an  abundance  of  energy'  when  in  operation.  The  instrument  is  fitted  with  an  experi¬ 
mental  circuit  for  demonstrating  the  laws  and  performing  the  many  interesting  and  instructive 
experiments  pertaining  to  high  frequency  phenomena. 

Our  coils  are  built  for  service,  only  the  best  of  material  being  used  in  their  construction.  They  are 
built  on  lines  that  positively  avoid  the  danger  of  expensive  “break-downs,”  such  as  are  met  with  in 
the  old  style  of  induction  coils.  Each  coil  is  fully'  guaranteed  against  mechanical  and  electrical 
imperfections. 

The  instrument  is  finely'  finished  throughout  and  is  furnished  in  a  polished  magohany  case.  All 
metal  parts  are  neatly  polished  and  lacquered. 

Complete  with  connecting  cord  and  Edison  plug  and  with  complete  directions  for  care  and  use.  .  $140.00 

95-376  HIGH  FREQUENCY  PHENOMENA  APPARATUS.  For  the  convenience  of  teachers  who  desire 
to  give  a  course  in  high  frequency  currents  we  have  designed  apparatus  capable  of  performing  all 
the  experiments  outlined  on  the  following  page  and  many  others  incapable  of  adequate  illustration. 

This  line  of  apparatus  is  well  made,  and  finished  and  guaranteed  satisfactory  in  every  respect. 

All  the  instruments  have  been  tested  with  the  previously  listed  coils  and  the  instructive  and  inter¬ 
esting  results  obtained  have  fully  warranted  a  place  in  our  catalogue. 

High  Frequency  Phenomena  Apparatus  sufficient  for  performing  all  the  experiments  outlined  on  the 
following  page.  In  neat  wooden  case  but  without  X-Ray  Tube . 35.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


38i 


HIGH  FREQUENCY  PHENOMENA 

ILLUSTRATING  TWENTY-FIVE  OF  THE  MANY  POSSIBLE 

EXPERIMENTS 


Transformation  in¬ 
to  Static  Electric¬ 
ity 


Brush  Discharge  Brush  Discharge  Discharge 
from  Hand  Ozone  Generator  from  Wire 


Destruction  of 
Dialect  ric 


Electric  Whirl  Effect  of  Air  Blast 
on  Discharge 


Molecular 


X-Rays 

Radiography 

Fluoroscofy 


' 


Lighting  VacuumTube 
without  connection 
Electro  Static  field 


Hysteresis 
Heating  Iron 


Self  Induction 
Marked  Drop  in 
Voltage 


Stepping  up  Voltage 
with  forced  oscilla¬ 
tions  in  self  indue 
tion  helix 


Resonance  in 
Helix 


High  Voltage  <-lirrAre  Resistance  ,J,tra  Violet  Li5ht  , ,  ,  v*ry  Radiation  through 

Resonant  Helix  Surface  resistance  Flu0resence  High  Freq -  ~  •  3 


Jcjuency  Dialectic 


382 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


COMMERCIAL  WIRELESS  APPARATUS 


The  educational  value  of  Wireless  Telegraphy  an<l  High  Frequency  Apparatus  cannot  be  overestimated.  Hold- 
inn  the  attention  of  the  student  and  scientist  alike  with  a  wonderful  fascination,  it  has  been  the  means  of  awaken¬ 
ing  an  interest  in  school  work  where  all  other  devices  have  failed. 

Tt  is  not  unusual  today  to  hear  pupils  in  the  elementary  grades  speaking  in  a  comprehending  manner  of  wave 
fronts,  vibrations,  resonance,  attuned  circuits,  potentiometers,  variable  condensers,  and  like  subjects  and  phenomena, 
that  a  few  years  ago  were  understood  only  by  advanced  students  of  science.  It  can  hardly  be  realised  that  stu¬ 
dents  in  the  grammar  schools  have  been  enabled  through  their  interest  in  this  class  of  apparatus  to  so  master  the 
subject  as  to  be  capable  not  only  of  designing  and  building  working  outfits,  but  also  of  reaching  such  a  degree  of 
proficiency  in  operating  them  as  to  be  employed  as  expert  operators  in  commercial  stations. 

Wireless  apparatus  should  be  installed  in  every  school  taking  up  the  study  of  Physics,  for  it  will  be  found  to  be 
the  one  set  of  apparatus  in  the  laboratory  that  will  hold  the  students’  attention,  (.'tubs  will  be  formed,  and  the 
students  will  take  the  greatest  interest  in  getting  into  communication  with  neighboring  schools  fitted  with  apparatus, 
and  one  and  all  will  endeavor  to  excel  in  proficiency  and  understanding  of  the  subject. 

The  installation  of  apparatus  itv  extremely  simple,  requiring  but  little  more  thought  and  time  than  the  installa¬ 
tion  of  an  ordinary  telegraph  instrument.  In  many  sections  of  the  country  the  apparatus  is  interesting  in  that  it 
furnishes  a  ready  means  of  obtaining  standard  time  which  is  given  out  daily  from  the  important  government  sta¬ 
tions.  So  much  apparatus  of  purely  amateur  design  and  construction  has  been  offered  for  school  work  that  we  feel 
that  the  sin  cess  of  the  instruction  in  this  field  has  been  seriously  handicapped.  For  this  reason  we  have  decided  to 
offer  the  only  standard  types  of  commercial  instruments,  built  by  manufacturers  of  the  widest  experience  in  install¬ 
ing  commercial  outfits. 


96  400  COMPLETE  SENDING  OUTFIT.  This  is  a  compact 
outfit  comprising  Transformer,  Condenser,  Helix, 

Spark  Gap  and  Key  mounted  in  and  on  a  finely 
finished  mahogany  cabinet.  It  is  shipped  ready 
for  use  and  has  but  to  be  connected  to  any  conven¬ 
ient  source  of  110-volt  alternating  current  and  a 
suitable  antenna. 

Complete  as  above  described . $44.00 


No.  96  400 


No.  96-406 


96  406  COMPLETE  RECEIVING  SET.  This  is  a  combination  of  instruments  mounted  in  a  well-finished 
mahogany  cabinet  with  hinged  cover.  This  set  includes  a  Ferron  Detector,  a  Receiving  Trans¬ 
former,  a  Fixed  Condenser,  a  Rotary  Variable  Condenser,  and  a  2000-ohm  Telephone  Head  set. 
Binding  Posts  are  provided  for  antenna,  ground  and  receiving  connections. 

1  lie  compactness,  accessibility  and  efficiency  of  this  instrument  will  appeal  to  any  one  interested  in 
the  subject. 

Complete  Receiving  Set  ....  . . 


$40.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


383 


SEPARATE  WIRELESS  UNITS 


We  list  below  a  line  of  high-grade  separate  units  for  the  benefit  of 
those  who  are  already  partialh  equipped  or  who  may  wish  to  construct 
for  themselves  a  part  of  their  wireless  apparatus.  The  design  of  the  units 
is  of  the  very  latest  commercial  types  and  such  as  will  appeal  to  those 
desiring  to  do  high-grade  work  in  the  wireless  field. 


No.  96-410 


SENDING  APPARATUS  IN  SEPARATE  UNITS 


96  410 


96-416 


TRANSFORMERS.  High  efficiency,  high  power,  low  heating  factors  and  reliable  service.  Each 
instrument  is  mounted  in  mahogany  cabinet,  the  secondary  sections  being  instantly  removable 
without  injuring  the  transformer.  The  primary  may  also  be  drawn  from  the  tube  without  inter¬ 
fering  with  the  secondary. 

a  be 

K  H  IK.  W. 

Each . $33.00  49.00  67.00 

HIGH  POTENTIAL  CONDENSERS.  Each  condenser  is  mounted  in  a  box  with  separate  connec¬ 
tions  brought  out  from  each  unit  so  that  the  capacity  may  be  varicdTy  connecting  in  various 
sections.  This  form  of  condenser  will  save  an  enormous  amount  of  energy  which  is  frequently 
lost  in  the  condenser  system.  It  will  conserve  the  great  power  of  our  transformers  as  no  other 
condenser  can.  With  this  type  of  condenser  the  efficiency  of  a  station  is  often  doubled. 


Each 


a 

}-i 

$12.40 


b  c 

K  1  K.  W. 

24.60  48.00 


No.  95-420 


96-426 


No.  96  430 

96  420  HELIX.  This  helix  is  the  one  employed  in  No. 

96-400  Transmitting  Set.  It  is  simple  and 
rugged  in  construction,  of  unusual  efficiency, 
employing  us  it  does  edge-wise  wound  copper 
strips.  The  base  is  of  finished  mahogany; 
supported  on  hard  rubber.  Three  clips  un¬ 
provided  for  varying  the  degree  of  coupling  . 

OSCILLATING  TRANSFORMER.  Our  yi,  and  1  K.  W.  sending  inductances  arc  of  the  in¬ 
ductively  coupled  type,  having  the  right  amount  of  coupling  to  produce  a  high  defined  wave  and 
perform  close  tuning  at  the  receiving  station.  The  primary  is  of  copper  ribbon  wound  spirally. 
The  secondary  is  of  copper  ribbon  wound  on  especially  prepared  drums,  lloth  circuits  have  vari¬ 
able  inductances  which  insure  absolute  resonance  between  the  two  circuits,  insuring  the  radiation 
of  a  greater  amount  of  energy  in  the  form  of  waves,  instead  of  the  energy  being  wasted  in  heat  at 
the  spark  gap.  This  Oscillator  is  designed  for  the  production  of  wave  lengths  of  from  600  amperes 
to  9o0  amperes  efficiency. 

a  be 


Each 


$21.00 


21.00 


1  K.  W. 

44.00 


96-430  ADJUSTABLE  SPARK  GAPS.  No  part  of  a  sending  set  is  more  likely  to  cause  loss  of  energy  than  a 
poorly  constructed  spark  gap.  In  many  instances  efficiency  is  cut  down  one-half  through  loss  at 
this  point.  In  our  instruments  we  use  an  especially  prepared  zinc  electrode,  capable  of  with¬ 
standing  heavy  currents . 


$6.76 


6.60 


384 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


RECEIVING  APPARATUS  IN  SEPARATE 

UNITS 

DETECTORS 


No.  95-435  No.  95-440 

Patented  Patented 


95— 435  SILICON  DETECTOR.  This  form  of  Detector  is  well  known  to  all  who  are  interested  in  wireless 

apparatus,  and  some  of  the  longest  records  have  been  made  with  this  type  of  instrument.  It  is 
fully  guaranteed  and  furnished  to  us  by  a  manufacturer  especially  licensed  by  the  inventor  .  .  .  $6.50 

96- 440  IMPROVED  FERRON  DETECTOR.  The  new  Ferron  Detector  is  made  up  of  a  metallic  crystal 

held  in  a  nickeled  cup,  mounted  on  the  usual  form  of  detector  stand.  An  exceedingly  fine  adjust¬ 
ment  of  pressure  is  easily  obtained  by  means  of  a  triple  spring  operated  by  a  milled  head  rubber 
rod.  Mounted  on  substantial  marble  base  5^X3  inches.  This  Detector  is  simple  and  operates 
best  without  either  Potentiometer  or  battery .  6.25 


No.  95-446 


95—445  TUNING  COIL  of  the  loose  couple  type.  This  instrument  has  been  especially  designed  for  educa¬ 
tional  institutions  where  it  is  desirable,  in  order  to  show  the  construction  of  the  essential  working 

parts,  to  withdraw  entirely  the  primary  from  the  secondary  coil. 
Special  provision  has  been  made  for  this  so  that  it  may  be  drawn 
fully  from  the  secondary  and  inserted  without  danger  of  binding. 
The  adjustment  is  easy  and  positive.  The  primary  of  the  coil  is 
of  unusual  capacity,  enabling  the  shortest  and  longest  wave  lengths 
used  by  commercial  stations  to  be  received  with  a  comparatively 
small  antenna,  and  without  the  use  of  additional  inductances  or 
condensers.  The  secondary  is  made  much  larger  than  is  usual  and 
mounted  on  pivoted  wheels . 

95— 450  HEAD  BAND  RECEIVERS.  Double,  2000-ohm  resistance  .  .  . 

96— 455  FIXED  CONDENSER.  The  most  approved  methods  of  connect¬ 

ing  a  modern  receiving  station  require  a  small  condenser  of  fixed 
capacity  in  addition  to  the  variable  condenser  used  in  tuning 
purposes.  It  is  mounted  in  a  nickel-plated  brass  cylinder  fitted 
with  hard  rubber  top  carrying  binding  posts.  Its  capacity  is 
approximately  .003  M.  F . 


VARIABLE  AIR  CONDENSERS.  See  page  388. 


$15.00 

12.00 


2.30 


No.  95-455 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


385 


ELECTROLYTIC  RECTIFIERS 


96-485  ELECTROLYTIC  RECTIFIER,  Nodon  valve  type, 
designed  for  use  on  110-volt  alternating  current, 
giving  a  direct  current  of  the  pulsating  form,  but 
one  in  which  the  negative  part  of  the  wave  is  en¬ 
tirely  cut  off,  so  that  for  most  purposes  this  trans¬ 
formed  current  takes  the  place  of  a  direct  current 
of  equal  voltage.  The  charging  of  storage  batter¬ 
ies,  experiments  in  electrolysis,  charging  of  electro¬ 
magnets,  complete  series  of  experiments  showing 
the  mutual  attraction  and  repulsion  of  currents, 
etc.,  may  be  performed  with  this  current. 

The  valve  here  illustrated  is  of  substantial  construc¬ 
tion,  jars,  lead  plates,  aluminum  rods  of  generous 
proportions,  slate  top  and  connectors,  substan¬ 
tial  iron  rod  support  and  wooden  carrying  case. 

Full  directions  for  connections  and  use  furnished 
with  each  instrument. 

Large  amperage  may  be  drawn  from  this  instrument, 
but  for  brief  periods  only,  owing  to  the  fact  that 
no  adequate  arrangements  have  been  made  for 
radiating  the  heat. 

Complete . $14.76 


No.  95-486 


96-490  THE  NEW  MULTIPLE  RANGE  SELF- 
COOLING  RECTIFIER,  with  ammeter, 
designed  for  use  on  110- volt  alternating 
current  and  to  deliver  a  direct  current 
of  varying  voltages.  As  ordinarily 
furnished,  3,  6,  9,  and  12  volts  have 
been  provided  for,  being  the  ranges 
most  generally  useful  in  laboratory 
work.  In  addition  to  these  a  12-volt 
alternating  current  may  also  be  drawn. 
As  will  be  noted  from  the  illustration, 
the  instrument  is  provided  with  an 
ammeter  so  that  the  exact  consumption 
on  the  direct  current  circuit  may  be 
noted  constantly. 

The  terminals  on  the  top  of  the  case  are 
connected  to  various  sections  of  the 
transformer,  each  clearly  marked  so 
that  the  user  can  tell  at  a  glance  what 
voltage  he  is  drawing. 

No.  96-490  General  construction.  Owing  to  the  care 

Patent  Pending  which  has  been  taken  to  properly  dissi¬ 

pate  the  heat,  large  amperage  may  be 
drawn  from  this  instrument  continuously.  The  metal  case  is  made  with  radiating  vanes,  the 
case  itself  serving  as  one  of  the  electrodes,  so  that  the  heat  generated  is  taken  care  of  by  con¬ 
duction  and  radiation  as  fast  as  produced. 

This  outfit  will  be  found  not  only  much  more  convenient  to  use  than  the  electrolytic  rectifiers  of 
the  type  No.  96-485,  but  is  also  much  more  efficient.  The  fact  that  multiple  voltages  can  be 
drawn  enables  it  to  fill  a  need  in  laboratory  work  which  has  long  been  felt.  These  instruments 
should  be  provided  in  every  laboratory  where  a  direct  current  of  low  voltage  is  not  already  pro¬ 
vided  for. 

Complete  directions  furnished  with  each  instrument. 


Complete  with  ammeter,  mounted  as  shown  in  the  illustration 


$38.00 


=jiitl& 


386 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ROTARY  CONVERTERS 


Nos.  95-500  to  95-506 

Our  Rotary  Converters  are  of  the  same  high  quality  as  are  our  Generators  and  Motorsilisted  in  Section  97.  The 
conversion  of  the  Direct  to  the  Alternating  current  is  accomplished  with  the  highest  efficiency  output.  They  are 
guaranteed  against  mechanical  and  electrical  imperfections. 

Prices  include  Automatic  No-voltage  Release  Starting  Box. 

Price 


Output 

Watts  Speed 

no 

Volts 

Input 

220 

95-600 

75 

3600 

$50.00 

$53.00 

95-602 

100 

3600 

52.50 

56.50 

95-604 

150 

3600 

56.00 

68.00 

96-606 

250 

1800 

60.00 

64.00 

MOTOR  GENERATORS 


LC. KNOTT  APPARATUS  CO. 
HOST  ON 


Nos.  95-610  to  95-620 

These  Motor  Generators  are  intended  for  those  schools  which  have  an  available  Alternating  Current  and  which 
desire  a  Direct  Current.  Our  line  listed  below  is  of  standard  quality  guaranteed  against  mechanical  and  electrical 
defects. 

Prices  include  suitable  rheostat  when  needed. 


A.  C.  Motor. 

60  cycle,  single  phase 

1740  RPM,  110  or  220  volts 
H.  P. 

Generator 

Watts 

Price 

95-510 

% 

60 

$80.00 

95-512 

V4 

120 

96.00 

95-616 

y2 

175 

142.00 

95-517 

% 

250 

165.00 

96-620 

i 

500 

216.00 

CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


387 


INDUCTANCE  AND  CAPACITY  APPARATUS 


Nos.  96-10  to  96-40  Nos.  96-60  to  96-62 


STANDARD  SELF-INDUCTION  COILS.  The  knowledge  of  exact  measurements  in  the  matter  of  self-induction 
and  capacity  is  of  the  greatest  importance  in  setting  up  and  in  the  use  of  machines,  measuring  instruments,  and 
apparatus  operated  by  alternating  currents,  as  in  installing  of  telegraph  and  telephone  apparatus,  cables,  and  cir¬ 
cuits  of  all  kinds.  By  the  use  of  standard  self-induction  coils  and  simple  measuring  appliances  it  is  possible  to  de¬ 
termine  these  values  very  exactly. 

The  self-induction  coils  below  listed  have  been  prepared  in  accordance  with  the  principles  laid  down  by  the 
Reichsanstalt.  They  are  spools  of  wire  of  known  self-induction  wound  upon  cylinders  of  serpentine,  wholly  free 
from  iron  and  immovably  fixed  upon  these  cylinders. 

These  spools  are  so  encased  in  a  vulcanized  rubber  covering  that  they  are  protected  against  injury  from  the 
outside.  By  avoiding  all  metal  parts  except  very  small  clamps,  and  by  the  divisions  of  the  turns  of  the  coil  the  pres¬ 
ence  of  eddy  currents  is  effectually  avoided. 

The  standards  are  tested  with  great  care  to  .002  of  their  stated  value. 

96-10  STANDARD  SELF-INDUCTION  COIL,  capacity  1  Henry  . Duty  Free  .  .  . 

96-12  - ,  capacity  0.5  Henry  .  . .  “  “  .  .  . 

96-14  - ,  capacity  0.1  Henry .  “  “  .  .  . 

96-16  - ,  capacity  0.01  Henry .  “  “  ... 

96-17  - ,  capacity  0.001  Henry .  “  “  ... 

96-19  - ,  capacity  0.0001  Henry .  “  “  ... 

96-30  STANDARD  SELF-INDUCTION  SPOOLS,  same  as  above,  but  wound  on  marble  spools;  capacity  .  .  . 

1  Henry . Duty  Free  .  .  . 

96-32  - ,  capacity  0.5  Henry . 

96-34  - ,  capacity  0.1  Henry . 

96-36  - ,  capacity  0.01  Henry . Duty  Free 

96-38  - ,  capacity  0.001  Henry .  “  “ 

96-40  - ,  capacity  0.0001  Henry .  “  “ 

96-60  AYRTON  and  PERRY’S  VARIABLE  STANDARD  OF  SELF-INDUCTION, 

reading  directly  to  Millihenrys,  range  from  4  to  40  Millihenrys.  Wood 
mounting . Duty  Free 

96-62  -  — ,  same  as  above,  but  constructed  of  ebonite .  “  “ 

96-60  ADJUSTABLE  INDUCTANCE.  These  inductances  are  made  up  of  copper 
wire  wound  on  a  threaded  hard  rubber  tube,  —  a  construction  that  has 
been  found  to  give  excellent  results  both  mechanically  and  electrically. 

A  smooth-acting  slide  permits  any  desired  amount  of  the  wire  to  be  placed 
in  circuit,  and  a  scale  on  the  slide  support  gives  the  value  of  the  portion 
in  use. 

These  inductances  will  be  found  well  suited  and  convenient  to  use  in  con- 
necton  with  High  Frequency  currents  and  Wireless  Telegraph  outfits. 

Capacity  1000  Microhenrys . $1 

96—66  - ,  same  as  above,  capacity  5000  Microhenrys .  26.00  Nos.  96-60  to  96-66 


388 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


96-106 

96-110 

96-116 

96-117 

96-125 

96-136 


•  » 


CONDENSERS 


Nos.  96-136  to  96-140 


CONDENSERS,  paper  and  tinfoil  rolled  type.  These  condensers  have  a  guaranteed  capacity,  and 
the  average  insulation  resistance  of  100  megohms  and  not  less  than  50  megohms  per  micro-farad. 


a  b  c 

Capacity .  1  2  M.  F. 

Each  .  $1.20  1.30  2.10 


SUBDIVIDED  PAPER  CONDENSER,  V2  to  2  M.  F.  by  y2  M.  F.  steps.  Enclosed  in  polished 

wooden  case  . 

SUBDIVIDED  PAPER  CONDENSER,  excellent  grade,  capacity  one  micro-farad,  subdivided  into 
four  steps,  —  0.1,  0.2,  0.2  and  0.5  M.  F.  Enclosed  in  polished  wood  case  as  illustrated  under 
No.  96-117 . 


- ,  same  as  above,  but  capacity  2  M.  F.  subdivided  into  five  steps,  —  0.1,  0.2,  .0.5  and  1  M.  F. 

MICA  CONDENSERS.  These  condensers  are  constructed  by  an  improved  process  in  which  the 
mica  leaves  are  silvered  on  both  sides.  This  direct  deposit  of  metal  without  any  foreign  sub¬ 
stance  permits  of  the  full  dielectric  properties  of  the  mica.  It  will  be  noted  also  that  the  deposit 
of  silver  adhering  so  closely  to  the  mica  forms  a  perfect  condensing  surface.  It  will  be  found  by 
actual  tests  that  the  stated  capacities  remain  constant. 

a  b  c  d 

Capacity .  0.1  0.2  0.5  1  M.  F. 

Each,  Duty  Free  ........  $22.40  30.00  38.50  69.00 

VARIABLE  AIR  CONDENSER.  This  is  a  standard  instrument  constructed  of  the  highest  quality 
material  and  of  first-class  workmanship  throughout.  The  vanes  are  of  aluminum,  and  the  moving 
system  works  perfectly  without  interference  of  the  plates  or  other  objectionable  features  commonly 
met  with  in  instruments  of  cheaper  construction.  The  top  is  of  the  best  grade  hard  rubber,  insuring 
high  insulation  and  durability.  A  binding  post  is  provided  connecting  to  the  case  for  grounding  in 
experiments  where  the  utmost  accuracy  is  required.  These  condensers  will  be  found  of  great  use¬ 
fulness  in  wireless  telegraphy  and  in  experiments  with  currents  of  high  frequency.  Capacity  .001 
M.  F . 


$6.75 

32.40 

40.00 


28.00 


96-140 


,  similar  to  above,  but  with  a  capacity  of  .005  M.  F 


42.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


389 


ELECTRO-DYNAMIC  APPARATUS 

DYNAMOS  AND  MOTORS 


No.  97-10 


No.  97-25 


No.  97-30  No.  97-40 


97-10  MOTOR  PARTS,  complete  parts  for  assembling  a  working  motor.  The  popularity  of  the  outfit 
above  illustrated  has  demonstrated  its  efficiency  as  a  pedagogic  instrument.  All  parts  ready  to 
wind  and  assemble  are  enclosed  with  simple  directions  in  a  neat  cardboard  box.  These  parts  and 
directions  may  be  placed  in  the  hands  of  any  ingenious  pupil  who  may  readily  assemble  a  motor 
for  himself . $1.26 

97-15  SIMPLE  MOTOR.  This  motor  though  simple  is  well  and  substantially  made.  It  is  finished  in  black 
enamel  with  nickel-plated  trimmings;  mounted  on  polished  wood  base.  It  weighs  about  1  pound 
and  occupies  a  space  3  X  334  X  4  inches. 

It  will  run  efficiently  on  a  single  battery  cell .  1.60 

97-17  SERIES  WOUND  DYNAMO,  same  simple  and  substantial  structure  as  above.  Effectively  used 

with  above  in  combining  a  simple  Motor  Generator .  2.00 

97-26  STANDARD  MOTOR.  This  motor  is  built  for  efficiency.  It  is  designed  to  operate  on  two  or  three 
cells  of  battery.  Will  run  about  2200  R.  P.  M.  with  average  load  on  a  current  of  2  amperes  at  4 
volts. 

Finished  in  black  enamel  with  brass  terminals.  Weighs  about  134  pounds;  occupies  a  space  about 

334  inches  square  .  3.25 

97-30  REVERSING  LEVER  MOTOR.  This  motor  is  similar  in  design  to  No.  97-40,  though  built  on  a 
smaller  plan.  It  is  wound  for  battery  current  only  and  runs  to  full  efficiency  on  two  or  three  dry 
cells.  Stands  about  3 34  inches  high  and  weighs  about  15  ounces. 

A  feature  of  this  motor  is  the  reversing  lever  designed  to  start,  stop,  and  reverse  the  motion  of  the 
armature .  .  3.75 

97—40  AIR-COOLED  MOTOR.  This  small  motor,  standing  3%  inches  high  and  weighing  20  ounces,  is  built 
on  the  lines  of  large  machines.  With  the  exception  of  the  base  no  cast  iron  is  used  in  its  construction. 

The  field  is  made  of  the  best  charcoal  iron,  annular  field  coil  carefully  taped  and  shellaced.  The 
armature  is  laminated  and  slot  wound.  It  is  provided  with  self-lubricating  bearing  so  constructed 
as  to  always  be  in  perfect  alignment,  the  cups  having  covers.  The  commutator  segments  are  of 
hard  copper  carefully  insulated  with  mica.  Brushes  are  self-adjusting.  Steel  armature  shaft 
fitted  with  grooved  brass  pulley  %  inch  in  diameter.  This  motor  is  handsomely  finished  through¬ 
out,  the  frame  and  base  being  finished  in  black  enamel.  It  is  highly  recommended  as  a  most  power¬ 
ful  battery  motor .  4.60 


390 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  97-60 


97-60  STUDENTS’  MOTOR  GENERATOR  for  the  study  of  the  construction  and  operation  of  a  simple 
dynamo  and  motor.  This  is  a  complete  power  station  in  the  smallest  practical  size  for  students’ 
laboratory  work.  The  general  design  is  such  as  all  doubtless  are  already  familiar  with,  but  made  of 
much  higher  quality  of  workmanship,  and  consequently  more  efficient. 

The  motor  is  wound  for  a  4-volt  battery  current,  the  dynamo  is  series  wound,  and  proportioned  to 
give  the  best  possible  results  as  a  generator,  notwithstanding  its  small  size.  The  dissectible  features 
of  both  dynamo  and  motor  are  important  for  both  laboratory  instruments.  They  will  be  found 
valuable  educational  instruments  in  studying  the  complete  transformation  of  electrical  energy  from 
the  battery  through  the  motor,  dynamo,  and  galvanometer.  \ 

Both  instruments  are  mounted  and  clamped  to  a  neatly  polished  wooden  base  and  direct  connected  by 
a  short  belt.  With  the  use  of  this  combination  a  student  is  able  to  compare  the  parts  of  the  dynamo 
with  the  corresponding  parts  of  the  motor,  to  observe  points  of  similarity  and  points  of  difference. 

The  instrument  utilizes  our  popular  Turner  Base  and  Clamp  which  binds  both  motor  and  dynamo  in 

correct  alignment  in  a  simple  and  efficient  manner .  $3.95 


97-62  TURNER  AND  HERSEY  BED  CLAMP  for  small  power  station.  This  base,  as  supplied  in  above 
apparatus,  is  designed  for  easy  and  effective  coupling  of  a  motor  and  dynamo.  In  students’  ex¬ 
perimental  work  it  is  necessary  that  the  two  units  be  held  rigidly  in  position,  but  that  sufficient  ad¬ 
justment  be  allowed  for  readily  tightening  the  belt.  The  metal  clamps  provide  an  easy  and  ef¬ 
fective  method  of  regulating  the  distance  and  of  tightening  the  belt. 

Complete .  46 


97-70  DYNAMO-MOTOR,  field  of  soft  gray  iron,  armature  —  eight  sections  of  the  laminated  tunnel 
drum  pattern,  shunt  wound  with  silk  enameled  wire,  commutator  eight  sections  amply  insulated 
with  large  carrying  capacity,  brushes  of  best  pattern  and  quality,  bearings  of  brass  with  large 

oil  cups,  finish  bright  enamel  and  nickel-plate, 
mounted  on  polished  wood  base  4%  X  5H 
inches. 

As  a  Dynamo  its  output  at  full  speed  of  3.000 
to  3200  R.  P.  M.  is  about  30  watts  (12  volts 
and  2.5  amperes).  It  will  be  found  very  use¬ 
ful  for  furnishing  current  for  many  experi¬ 
ments  in  the  study  of  Electricity  and  Mag¬ 
netism.  It  will  charge  a  six-volt  40-ampere- 
hour  storage  battery  in  12  hours. 

As  a  Motor  it  operates  on  6  to  12  volts  of 
battery  current,  giving  about  1800  R.  P.  M. 
at  8  volts  and  2500  R.  P.  M.  at  12  volts.  It 
will  develop  about  %6  H.  P. 

This  Dynamo-Motor  is  furnished  with  a  pulley 
1 Y2  inches  in  diameter,  V-groove  for  a  %o-inch 
round  belt . . 


V 


No.  97-70 


7.76 


_ _ 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


391 


I 


No.  97-100 


vJ 


t...  SET-UP  WITH  4-POlE  ARMATURC 

K--.V.V . -v.. 


Fields 


Arm  with 

Brushes 


e-Pole  Field 


No.  97-100  (Fig.  1) 


2-POLE  ARMATURE 

Fig.  2 


3-  POLE  ARMATURE 

Fig.  3 


.•POLE  ARMATURE 

'  Fig.  4 


97-100  MOTOR  DYNAMO  DEMONSTRATION  APPARATUS.  • 

From  an  educational  point  of  view,  teachers  will  appreciate  the  open  construction  and  the  ease  with 
which  the  student  may  see  at  a  glance  the  various  poles  of  either  type  of  dynamo  or  motor,  and  in 
consequence  be  free  from  the  perplexing  problem  of  determining  the  exact  position  of  the  pole. 

Some  of  the  points  that  may  be  easily  studied  by  the  student  are  briefly  outlined  as  follows:  — 

1.  The  two-pole  Magneto. 

2.  The  two,  three,  or  four-pole  Armature  in  a  two-pole  field. 

3.  The  effect  of  varying  the  strength  of  the  field. 

4.  Shunt-wound  Motors  having  like  or  unlike  number  of  armatures  and  field  poles. 

5.  Series-wound  Motors  having  like  or  unlike  number  of  armatures  and  field  poles.  (This  point 
is  rendered  especially  easy  since  all  the  armatures  are  interchangeable  with  all  the  field  systems 
so  that  they  are  easily  combined  in  any  desired  manner.) 

6.  A  study  of  the  neutral  point. 

7.  A  study  of  the  effect  of  changing  the  direction  of  the  current  in  either  armature  or  field.  Many 
other  experiments  applicable  to  the  Dynamo  and  Motor  may  be  readily  performed.  Price  com¬ 
plete  with  3  Armatures, 

6  Field  Coils, 

2  Bar  Magnets . - . $3.86 

97-106  METAL  MOUNTED  IMPROVED  ST.  LOUIS  MOTOR,  with  Im¬ 
proved  Brush  Carrier  and  Armature. 

This  apparatus  is  an  improved  form  of  the  apparatus  known  as 
the  St.  Louis  Motor.  It  may  be  used  as  a  dynamo  or  motor.  Al¬ 
though  similar  to  No.  97-100  in  its  application  to  principles 
of  dynamo  and  motor  construction,  it  is  limited  in  range  of 
experiments  possible.  It  serves  effectively,  however,  to  teach 
with  permanent  field  magnets,  — 

1.  Strength  of  magnet  field  at  different  distances  from  arma¬ 
ture. 

2.  Effect  of  two  like  and  effect  of  two  unlike  poles;  with  elec¬ 
tromagnet  field,  series  and  shunt  dynamo. 

It  is  a  simple  and  effective  means  in  individual  laboratory  work 
of  making  simple  and  clear,  —  No.  97-106 

1.  Polarity  of  armature  at  different  points  in  its  revolution. 

2.  Direction  of  current  in  armature  and  field. 

3.  Commutation,  position  of  armature,  commutator  and  brushes. 

Complete  as  illustrated,  with  permanent  and  electromagnet  attachments . $2.80 


392 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  97-115 

GILLEY  GRAMME  MACHINE 


No.  97-115  Fig.  1 


of  force  are  thus  permitted  to  arrange  themselves  under 
in  the  armature  and  field. 


The  Gramme  Machine  represents  a  type  of  generator 
now  generally  used  in  large  units  for  power  and  lighting 
stations.  The  Gilley  Gramme  Machine  is  a  modification 
so  worked  out  that  the  lines  of  force  may  be  easily  plotted 
by  the  compass  and  filings  method. 

No  other  apparatus  has  yet  been  designed  with  which 
it  is  possible  to  show  the  lines  of  force  in  a  working  model 
of  the  dynamo  and  motor  with  the  armature  in  position 
and  in  actual  operation.  Both  the  field  and  armature 
are  designed  and  made  in  flat  form,  so  that  the  upper  sur¬ 
faces  of  both  are  level,  permitting  the  paper  or  glass  upon 
which  the  lines  of  force  by  the  filings  method  are  to  be 
mapped  to  take  a  smooth  horizontal  position.  The  lines 
no  other  influence  than  that  of  the  magnetic  force  existing 


Dissectible  Features.  Fig.  2  shows  the  three  basic  parts  of  the  apparatus,  —  the  armature  with  the  commu¬ 
tator,  the  field  magnet  with  base,  and  the  brush-holder.  The  instrument  is  readily  dissected,  as  the  illustration 
shows.  Each  part  may  be  studied  separately,  as  will  be  noted  from  the  following  list  of  experiments. 

We  desire  to  call  attention  also  to  the  fact  that  the  field  coil  is  easily  removed  from  its  base  and  the  base  so 
designed  that  6-inch  permanent  magnets  may  be  substituted  for  the  field  coil,  thus  teaching  the  fundamental  prin¬ 
ciple  of  the  magneto. 


WHAT  THE  INSTRUMENT  IS  DESIGNED  TO  TEACH 

Experiment  1.  Study  of  the  field 
magnet  in  an  electromagnet,  the  lines 
of  force  being  mapped  out  either  by 
compass  or  filings  method. 

Experiment  2.  To  show  what  ef¬ 
fect  the  soft  iron  ring  of  the  armature 
has  upon  field  magnets.  The  value  of 
this  exercise  is  greatly  increased  by 
using  the  filings  method  of  mapping 
the  field  and  comparing  the  field  with 
results  obtained  above. 

Experiment  3.  A  detailed  study 
of  the  armature,  showing  that  it  is 
wound  in  sections  and  where  the  ends 
of  each  section  are. 

Experiment  4.  A  detailed  study 
of  the  commutator  by  passing  the 
current  into  the  armature  magnet 
through  the  brushes,  showing  by  this 
method  the  exact  position  of  each 
section  when  polarity  is  reversed. 
Experiment  5.  The  method  of  answering  definitely  why  the  armature  of  a  motor  rotates.  The  action 
of  the  lines  of  force  as  indicated  by  the  filings  method  will  make  this  clear. 

Experiment  6.  A  study  of  the  magneto  generator,  its  relation  to  the  regular  commercial  dynamo,  showing 
definitely  why  the  current  is  generated  when  the  armature  is  rotated  between  the  poles  of  a  magnet. 

Experiment  7.  A  study  of  the  magneto  and  its  relation  to  the  dynamo,  also  why  the  armature  in  a 
magneto  machine  rotates. 

Experiment  8.  A  study  of  the  dynamo  using  electromagnetic  field  and  armature.  Determining  the 
relation  of  the  armature  to  the  field  coils  and  the  speed  of  the  armature  to  the  strength  of  the  magnetic  field. 

Experiment  9.  The  study  of  different  types  of  dynamos  and  motors  depending  upon  whether  the  arma¬ 
ture  and  field  are  connected  in  series  or  in  multiple,  and  what  are  the  conditions  regulating  the  method  of 
connecting  in  any  given  machine. 

Experiment  10.  To  show  what  the  result  will  be  if  the  armature  is  removed  and  a  permanent  bar  magnet 
be  mounted  on  the  same  bearing.  This  experiment  teaches  clearly  the  reason  why  the  armature  must  be  an 
electromagnet  and  not  a  permanent  magnet. 

Gilley  Gramme  Machine . 


No.  97-116  (Dissected)  Fig.  2 


$7.76 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


393 


No.  97-125 


/ 

I 


MILLER-COWEN  ATTACHMENT  TO  GILLEY 

GRAMME  MACHINE 


This  attachment,  designed  by 
G.  A.  Cowen  and  F.  R.  Miller  of  the 
Boston  High  Schools,  further  in¬ 
creases  the  educational  value  of  the 
Gilley  Gramme  Machine  by  apply¬ 
ing  the  method  of  clear,  open  con¬ 
struction  as  used  in  that  machine 
to  the  parts  that  are  too  often 
neglected  but  the  operation  of  which 
is  of  the  utmost  importance.  This 
attachment  allows  of  the  removal  of 
the  armature  iron  so  that  experi¬ 
ments  may  be  conducted  either 
with  a  simple  revolving  armature 
coil  or  with  the  enclosed  iron  core 
as  desired. 

In  addition  to  a  large  commu¬ 
tator,  collecting  rings  are  provided 
for  the  proper  investigation  of  the 
alternating  type  of  motor  and  gen¬ 
erator.  A  handle  furnishes  a  ready 
means  of  revolving  the  armature. 


No.  97-125  (Dismounted  Field  Magnet) 


The  use  of  this  device  in  connection  with  our 
Universal  Galvanometer  No.  93-130  is  recom¬ 
mended,  as  it  is  built  to  work  in  connection  with 
an  instrument  of  its  range.  This  attachment  is 
carefully  constructed  and  most  rigidly  tested  in 
our  laboratory  before  shipment.  Each  instrument 
is  guaranteed  satisfactory,  and  its  design  will  com¬ 
mend  it  as  a  valuable  educational  instrument. 

Special  Features.  The  large  commutator  for 
both  A.  C.  and  D-  C.,  the  ready  means  of  chang¬ 
ing  brushes  to  make  contacts  with  either  A.  C.  or 
D.  C.  commutator  without  changing  the  galvanom¬ 
eter  connections,  the  ease  with  which  the  field  mag¬ 
nets  may  be  removed  and  bar  magnets  substituted, 
the  ready  removal  of  the  laminated  core,  are  fea¬ 
tures  which  make  it  an  educational  instrument  of 
the  utmost  value. 

As  a  dynamo  analysis  machine  of  simplest  form 
it  has  met  with  much  favor  in  vocational  schools. 


No.  97-126  (Mounted  Field  Magnet) 


97-125  MILLER-COWEN  ATTACHMENT,  including  the  Field  Magnet . $10.60 

97-127  MILLER-COWEN  ATTACHMENT,  without  the  Field  Magnet  for  those  who  already  have  No. 

97-116  Gilley- Gramme  Machine . 


8.00 


394 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  97-148 

DIRECT  CONNECTED  HAND  POWER 
DYNAMO  AND  MOTOR 


No.  97-148 


This  instrument  is  provided  with  coils,  collecting  rings  and  commutator  so  that  it  will  work  to  highest  efficiency 
in  the  production  of  either  alternating  or  direct  current.  As  ordinarily  used  on  the  lecture  table  the  output  may  be 
roughly  stated  as  15  volts  and  7  amperes,  but  a  greater  output  can  be  obtained  if  desired. 

Field  and  armature  may  be  connected  in  series  or  shunt,  making  it  possible  to  teach  definitely,  —  Direct  Current 

Shunt  Wound  Dynamo,  Self-Exciting  Alternating  Current  Dynamo,  Series  Dynamo  Motor,  Rotary  Converter  or 
Motor  Generator. 

SPECIAL  FEATURES: 

Dissectibility.  Pole  pieces  separated  and  armature  removed  without  the  use  of  wrench  or  screw 
driver.  Can  be  taken  apart  and  reassembled  on  the  lecture  table  while  the  lecture  is  in  process. 

Efficiency.  Will  easily  generate  100  watts  of  electrical  energy  and  is  guaranteed  to  give  200  watts, 

—  a  new  accomplishment  in  instruments  for  educational  work. 

Design.  Careful  study  has  been  made  of  commercial  types  which  we  have  modified  only  to  the 
extent  of  obtaining  the  dissectible  and  educational  features  which  we  consider  of  prime  importance. 

Driving  Mechanism.  In  eliminating  the  belt  and  substituting  the  enclosed  oil-immersed,  direct  con¬ 
nected  gear  drive,  a  long  step  in  advance  has  been  made  in  the  construction  of  Hand  Power  Dy¬ 
namos.  This  feature  had  in  part  been  worked  out  in  our  Hand  Power  Dynamo  No.  97-160,  the 
success  of  which  led  us  to  take  the  next  step  and  eliminate  entirely  the  losses  due  to  the  belt  drive. 

By  careful  estimate,  this  method  of  drive  gives  an  increased  efficiency'  of  about  60  per  cent. 

Field  Magnet.  Two-pole  type  which  allows  the  use  of  a  large  amount  of  iron  and  permits  of  a 
construction  which  makes  the  shortest  magnetic  circuit,  at  the  same  time  allowing  a  clear  view 
of  the  pole  pieces  and  their  relation  to  the  armature. 

Field  Coils.  Wound  on  thin-spun  metal  bobbins,  each  core  being  designed  for  a  definite  purpose, 
depending  upon  whether  the  instrument  is  to  be  connected  series  or  shunt  wound,  giving  the 
greatest  efficiency  for  each  type. 

Armature.  Drum  type,  which  has  proven  best  suited  for  withstanding  hard  usage.  The  coil  sec¬ 
tions  are  wound  in  slots  in  the  laminated  iron  core.  The  anchoring  of  the  coil  has  been  done  in  the 
most  perfect  workmanlike  manner. 

Commutator.  Larger  size  proportionately  than  would  be  used  on  a  regular  commercial  machine, 
for  the  reason  that  it  is  a  part  of  the  design  of  this  instrument  that  all  of  the  essential  features 
be  large  enough  so  that  the  students  can  readily  study'  their  functions. 

Collecting  Rings.  Placed  on  the  same  end  of  the  shaft  as  the  commutator,  a  design  which  sim¬ 
plifies  the  instrument.  The  attachment  holding  the  brushes  serves  both  for  alternating  and  di¬ 
rect  circuit,  thus  offering  a  ready  method  of  comparison.  Price . $40.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


395 


MAGNETO.  This  instrument  is  a  regular  commercial  dynamo  o:  the  permanent  magnet  type,  em¬ 
ploying  magnets  of  unusual  strength.  A  very  ernciect  armature  is  provided  with  crank  and  gears 
so  that  it  may  be  readily  operated  by  hand.  This  instrument  is  frequently  used  in  telephone  ex¬ 
changes  and  often  as  a  testing  instrument  in  locating  broken  circuits  in  cofls.  Its  operation  b 
similar  to  that  which  takes  place  in  the  Page  Motor  Apparatus  below.  Its  educational  value  b 
in  the  practical  and  powerful  effects  that  can  be  obtained  by  rsqng  permanent  magnets.  The 
earlier  forms  of  power  machines  were  built  on  thb  principle . 

97-160  PAGE  MOTOR  APPARATUS.  Thb  apparatus  will  be  found  of  great  value  in  teaching  the  basic 
principles  of  the  electric  motor  and  dynamo.  By  utilizing  the  horseshoe  magnet,  the  student 
b  not  confounded  with  the  unusual  shape  of  pole  pieces  as  met  with  in  most  motor  or  dynamo  ap¬ 
pliances.  It  wiH  also  be  seen  that  the  use  of  a  permanent  horseshoe  magnet  allows  the  armature 
and  its  commutator  together  with  the  brushes  to  be  laid  out  on  a  fat  surface  so  that  each  part  can 
be  seen  whether  as  a  unit  or  working  together.  If  desired,  the  lines  of  force  can  be  readily  plotted 
in  the  usual  method  by  bon  tilings.  Thb  instrument  can  be  used  either  as  a  generator  or  a  motor, 
as  desired.  By  slowly  moving  the  armature  by  hand,  a  clear  understanding  can  be  had  of  its 
operation. 

The  instrument  b  well  made,  employing  a  powerful  magnet,  so  that  it  can  be  depended  upon  to  give 
satisfactory  results  in  the  hands  of  students  . . 


97-166 


97-165  PAGE  MOTOR  APPARATUS,  ELECTROMAGNETIC  FIELD.  Thb  apparatus  b  particularly 
designed  to  show  in  a  clear  and  comprehensive  manner  the  action  of  an  electromagnet  as  used  in 
the  modern  motors  and  dynamos.  The  held  coils  are  mounted  on  a  soft  U-shaped  frame  corre¬ 
sponding  in  general  appearance  to  the  permanent  magnet  of  the  Xe.  97-160  Page  Motor  Appara¬ 
tus  above,  thus  permitting  direct  and  dear  comparisons  of  the  magnetic  fields.  The  armature 
provided  with  thb  outfit  still  farther  illustrates  the  actios  of  the  electric  current,  for  the  iron  used 
in  the  motor  apparatus  above  b  entirely  dbpensed  with,  the  rotation  bring  brought  about  by  the 
direct  action  of  the  electromagnet  add  on  a  solenoid.  Commutators,  binding  posts  and  brushes 
for  connecting  in  various  series  and  shunt  combinations,  are  placed  so  that  they  can  be  dearly 
inspected.  The  apparatus  wDI  operate  as  a  motor  on  two  ceils  of  battery. 

Thb  apparatus  b  constructed  accurately  of  the  bet  obtainable  material,  and  ah  parts  are  nicely  acted. 
It  wiH  be  found  a  valuable  instrument  in  the  tearhirg  of  electro-dynamics.  As  a  companion 
instrument  with  the  Page  Motor  Apparatus  Xo.  97-160,  a  direct  comparison  of  permanent  and 
electromagnetic  types  of  instruments  makes  an  interesting  study . 


96.65 


3.50 


9.75 


396 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  » 


MOTORS 

ALTERNATING  AND  DIRECT  CURRENT 

1/30  TO  1/4  H.  P. 

The  well-known  line  of  “Standard”  Motors  listed  on  this  page  is  guaranteed  to  be  mechanically  and  electri¬ 
cally  perfect.  The  solidity  of  construction,  the  correctness  of  design  coupled  with  the  unsurpassed  enameled  finish, 
place  them  at  once  at  the  head  of  all  motors.  The  material  used  is  the  best  that  can  be  obtained.  They  are  of  un¬ 
usually  high  efficiency  and  are  fully  as  durable  as  the  larger  size  machines.  They  may  be  absolutely  relied  upon 
for  years  of  satisfactory  service. 


Nos.  97-176  to  97-179  Nos.  97-181  to  97-183 

DIRECT  CURRENT  COMPOUND  WOUND  MOTORS 

Prices  of  series  or  shunt  wound  motors  on  application. 


Prices 


Number 

H.  P. 

Speed 

115 

Volts  230 

97-176 

Vso 

1150 

$14.16 

$16.60 

97-177 

V20 

1750 

16.86 

17.26 

97-179 

y8 

2000 

18.00 

19.80 

97-181 

H 

1150 

20.26 

22.00 

97-183 

Vs 

1750 

21.76 

23.26 

97-186 

Vs 

1150 

28.60 

30.00 

97-187 

% 

1750 

31.00 

34.60 

97-189 

V\ 

2000 

34.60 

38.00 

SINGLE  PHASE  INDUCTION  MOTORS 


Full  Load  Start 

60  Cycles 

Continuous  Duty 

Number 

H.  P. 

Speed 

115 

Prices 

Volts 

230 

97-200 

Vso 

1150 

$17.60 

$19.60 

97-202 

Vso 

1750 

16.00 

18.00 

97-204 

V20 

1150 

24.26 

26.26 

97-206 

V20 

1750 

21.00 

23.00 

97-208 

/1o 

1150 

27.60 

29.60 

97-210 

X 

1750 

23.76 

26.76 

97-212 

Vs 

1150 

29.26 

31.26 

97-214 

Vs 

1750 

28.76 

30.76 

97-216 

Ve 

1150 

44.00 

46.00 

97-218 

Vo 

1750 

40.00 

42.00 

97-220 

X 

1150 

64.00 

66.00 

97-222 

X 

1750 

61.00 

63.00 

97-260  CANVAS  FRICTION  BRAKE,  after  Fuller  and  Brown¬ 
lee  (Experiment  86) . $0.76 


Nos.  97-200  to  97-222 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


397 


Nos.  97-270  to  97-272  Nos.  97-274  to  97-278 

The  generators  listed  below  are  guaranteed  to  be  of  the  very  best  material  and  workmanship,  free  from  either 
electrical  or  mechanical  defects,  and  will  carry  their  rated  load  continuously  without  attaining  a  temperature  greater 
than  40°  Centigrade  in  excess  of  that  of  the  surrounding  air. 

Prices  are  for  compound  wound  generators  and  include  standard  pulley,  sliding  base  with  belt-tightening  attach¬ 
ment  and  wall  type  field  regulating  rheostat. 

The  speed  stamped  on  the  name  plate  of  each  dynamo  is  that  at  which  it  should  be  driven  when  it  is  desired 
to  operate  it  at  the  voltage  marked. 


Number 

K.  W. 

Number  of 

25  Watt 

16  C.  P.  Lamps 

Speed  115  and 
230  Volts 

97-270 

Vi 

20 

1850 

97-272 

% 

30 

1750 

97-274 

1 

40 

1650 

97-276 

60 

1550 

97-278 

2 

80 

1400 

Sire  Pulley  Price 


Diam. 

Face 

115  V. 

230  V. 

4 

2 

$48.00 

$61.00 

4 

2'A 

62.60 

66.00 

5 

iy2 

80.00 

84.00 

5 

3 

88.60 

93.00 

5V2 

YA 

110.00 

116.00 

No.  97-286 


97-286  CONTROLLER  MODEL.  The  above  illustrated  device  is  designed  to  illustrate  in  a  practical 
manner  the  method  of  controlling  the  speed  and  operation  of  the  modern  electric  railroad  motor. 

The  commutator,  resistances,  etc.,  are  well  worked  out  in  open  construction  so  that  the  various 
changes  that  occur  and  their  effects  upon  the  included  model  motor  may  be  noted  with  ease  and 
accuracy. 

The  construction  is  substantial,  parts  clearly  shown,  and  the  whole  design  well  suited  for  its  didactic 
purpose. 

Complete  as  illustrated  with  motor . $31.00 


398 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ELECTRO -DYNAMIC  CHARTS 


No.  97-300 


97-300  ELECTRO-DYNAMIC  CHARTS  for  demonstrating  the  principles  of  dynamos  and  motors.  These 
charts,  which  are  finely  lithographed  in  colors  and  mounted  on  heavy  cardboard,  are  of  ample 
size,  28  X  30  inches.  They  may  be  seen  across  the  largest  lecture  hall;  the  complex  mechanism 
of  the  dynamo  and  motor,  both  alternating  and  direct  current,  may  be  clearly  shown.  The  dif¬ 
ferent  windings,  connections,  armatures,  poles,  etc.,  are  greatly  magnified  that  they  may  be  readily 
seen.  Each  chart  is  mounted  in  a  frame  and  the  armature  is  rotated  by  means  of  a  crank  operated 
from  the  rear.  That  the  change  of  polarity  may  be  demonstrated,  change  of  poles  in  the  armature 
is  automatically  shown  by  different  colors,  one  color  for  the  North  pole  and  another  for  the  South 
pole. 

The  set  consists  of  charts  as  follows:. — 

Group  I.  Double  Chart  consisting  of;  — 

a.  1  Attachable  hinged  disc  for  the  dynamo. 

b.  1  Attachable  hinged  disc  for  the  motor. 

c.  2  Discs  for  Gramme’s  Ring. 

d.  1  Colored  disc  for  the  magnetic  field. 

e.  1  Double  Collector,  one  side  with  two  collecting  rings,  the  other  with  an  eight-segment 

commutator. 

f.  2  Brushes. 

g.  4  Connecting  Cords. 

With  the  above  Group  the  following  demonstrations  can  be  readily  performed:  — 

1.  Magneto  Electric  Machine,  2-pole  armature,  alternating  current. 

2.  Magneto  Electric  Machine,  2-pole  armature,  direct  current. 

3.  Two-pole  Dynamo. 

4.  Dynamo  with  Gramme’s  Ring  Armature. 

5.  Alternating  Current  Motor,  2-pole. 

6.  Motor  with  Gramme’s  Ring  Armature. 

Accessory  Chart  II  for  use  in  demonstrating  alternating  current  machines. 

Accessory  Chart  III  for  demonstrating  alternating  current  motor. 

Complete  as  above  listed . Duty  Free 


No.  97-305 


97-306  PROJECTION  FREQUENCY  INDICATOR  for  110 
A.  C.  Volt  Current.  This  instrument  is  designed 
primarily  to  show  on  the  screen  the  effect  pro¬ 
duced  by  an  alternating  current  on  an  electro¬ 
magnet.  The  length  of  the  vibrating  reed  is  such  as 
to  show  clearly  on  the  screen,  the  one-quarter  wave 
length,  the  one-half  wave  length,  and  the  three- 
quarter  wave  length.  In  use  the  instrument  is  con- 
.  nected  directly  to  110  volt  alternating  current  with¬ 
out  additional  resistance . 


$7.60 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


399 


Fig.  4  Fig.  3  Fig.  6 

No.  97-310 

WEINHOLD’S  ROTARY  FIELD  APPARATUS  for  the  study  of  the  essential  principles  of  an  in¬ 
duction  or  alternating  current  motor  for  either  two-phase  or  three-phase  currents,  demonstrating 
clearly  the  rotating  magnetic  fields. 

The  complete  apparatus  consists  of  a  substantial  base  on  which  are  mounted  the  current  distributing 
apparatus,  Figure  1,  connecting  wires,  and  necessary  devices  for  the  interchangeable  parts,  the 
one  illustrated  on  the  base  board  being  a  double  coil.  In  addition  there  are  furnished  accessory 
coils  as  follows:  Ferraris’  Double  Coil,  Figure  2;  Ferraris’  Triple  Coil,  Figure  3;  4-coil  Iron  Ring, 

Figure  4;  Ring  of  6  Coils,  Figure  5;  Magnetized  Needle  and  Iron-plate  Disc  with  agate  socket, 
closed  circuit  armature;  and  perforated  glass  plate  with  alcoholized  iron  filings. 

This  apparatus  permits  of  experiments  demonstrating  in  a  practical  manner  the  effect  of  the  rotary 
field.  In  use  from  4  to  6  cells  of  battery  are  required.  This  current  can  be  changed  into  an  alter¬ 
nating  current  or  rotary  current  by  the  distributing  apparatus.  This  current  is  made  to  pass 
through  the  twofold  or  three-fold  crossed  coils  of  wire  of  various  colors.  In  the  middle  of  either 
of  these  coils  may  be  placed  a  magnetic  needle  or  an  iron  disc.  By  the  rotation  of  the  distributing 
apparatus  there  is  produced  a  current  of  either  two  or  three  phases,  according  as  the  twofold  or 
threefold  ring  is  used,  and  the  bodies  placed  within  the  coils  rotate  under  the  influence  of  the  rotary 
field.  Instead  of  these  wire  armatures,  however,  an  iron  ring  of  4  or  6  coils  may  also  be  used. 

Such  rings,  Figures  1  and  3,  are  wound  with  wire  wrapped  with  a  covering  of  different  colors.  By 
means  of  such  rings  synchronous  rotation  may  be  produced  by  the  insertion  of  a  magnetic  needle  or 
an  iron  disc;  and  by  an  iron  ring  wound  with  copper  wire  (closed  circuit  armature)  non-synchronous 

The  lines  marking  the  direction  of  the  influence  of  the  rotary  field 
can  also  be  more  strikingly  shown  by  means  of  a  glass  disc  covered 
with  the  iron  filings  furnished  with  the  apparatus. 

This  instrument  is  of  substantial  structure,  all  parts  neatly  and  hand¬ 
somely  finished,  especially  designed  for  teaching  the  principles  in¬ 
volved.  The  rotating  parts  are  mounted  with  agate  caps  and  steel¬ 
bearing  points.  All  wiring  is  indicated  by  different  colors.  All 
connections  are  open  to  view  on  top  of  the  base.  The  base  is  of 
highly  polished  hardwood. 

Complete  with  full  directions  for  use . $40.00 

THREE-PHASE  CURRENT  MOTOR  MODEL  (Tesla  Motor)  for 
use  with  above  Weinhold’s  Rotary  Demonstration  Apparatus, 
for  the  study  of  a  rotary  current  motor. 

This  model  is  furnished  with  six  fields,  closed  circuit  armature., 
with  three  leads.  The  winding  is  made  in  three  colors  and  the 
connections  are  open  and  in  colors.  The  apparatus  is  practical, 
clearly  arranged,  and  shows  the  experiments  in  all  their  bearings. 

It  is  highly  recommended  as  an  additional  accessory  to  the  above 
outfit . 19.60 


rotation  can  be  produced. 


97-316 


No.  97-316 


ALTERNATING  CURRENT  DEMON¬ 
STRATION  APPARATUS 


97-310 


400 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


TELEGRAPHY  AND  TELEPHONY 

TELEGRAPH  INSTRUMENTS 


No.  98-20  No.  98-56 


98-10  TELEGRAPH  KEY,  nickel-plated  lever,  brass  frame,  gutta-percha  knobs,  improved  adjustment 

spring  holders,  all  parts  finely  finished,  without  legs . $1.90 

98-12  TELEGRAPH  KEY  PARTS,  after  Turner  and  Hersey  (Experiment  E100) . Set  1.00 

98-16  IMPROVED  SOUNDER,  unequaled  for  quick  action,  loudness,  and  clear  tone,  proportioned  scientifi¬ 
cally  correct,  brass  lever,  resistance  5  ohms .  2.60 

98-17  TELEGRAPH  SOUNDER  PARTS,  after  Turner  and  Hersey  (Experiment  E100) . Set  1.00 

98-20  TELEGRAPH  RELAY,  excellent  quality,  finely  finished  and  mounted  on  polished  mahogany  base 

with  ornamented  metallic  sub-base.  Standard  resistance  of  5  ohms .  3.40 

98-26  COMBINATION  KEY  AND  SOUNDER.  This  instrument  is  designed  to  fulfil  the  requirements  of 
a  short-line  apparatus.  The  sounder  magnets,  lever,  anvil,  and  key  lever  are  the  same  as  used  on 
the  preceding  instruments.  The  frames  for  holding  the  sounder  lever  and  key  lever  are  stamped 
from  wrought  iron  and  heavily  japanned.  The  base  is  constructed  of  polished  mahogany. 

This  instrument  will  give  entire  satisfaction  on  lines  up  to  five  miles  in  length.  Resistance  5  ohms  .  .  2.60 


TELEPHONE  INSTRUMENTS 


00 

No.  98-100  No.  98-106 


No.  98-110 


98-100  DEMONSTRATION  POSTLESS  BI-POLAR  RECEIVER.  As  may  be  noted  from  the  illustration, 
this  instrument  is  entirely  dissectible,  and  in  consequence  has  a  value  as  a  demonstration  instru¬ 
ment,  as  well  as  that  of  a  working  receiver.  All  parts  are  carefully  fitted  and  finished  and  the 

receiver  is  high  grade  in  every  respect . $1.46 

98-106  SOLID  BACK  WATCH  CASE  RECEIVER,  2J4  inches  diameter,  weight  6  ounces,  resistance  75 
ohms,  rigid  adjustment. 

This  is  a  simple  receiver  sufficiently  sensitive  for  practically  all  laboratory  work .  1.00 

98-110  SOLID  BACK  LONG-DISTANCE  TRANSMITTER.  This  transmitter  is  the  standard  commercial 
type  furnished  on  long-distance  telephones.  They  articulate  distinctly  and  plainly  with  no  up 
and  down  variations  or  sizzling .  2.00 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


401 


No.  98-125  No.  98-135 


98-125  TELEPHONIC  MICROPHONE.  This  instrument  illustrates  in  a  clear  and  comprehensive  manner 
not  only  the  microphone  but  the  adaptation  of  same  in  the  articulating  telephone.  It  is  in  reality 
two  instruments  in  one,  requiring  only  the  simple  adjustment  of  a  thumb  screw  to  change  it  from 
a  simple  contact  telephone  to  a  practical  working  telephone.  The  small  induction  coil  on  the  base 
shows  the  manner  of  raising  the  potential  of  the  telephonic  circuit,  which  is  inductively  connected. 
The  results  attending  the  connecting  of  the  instrument  with  an  ordinary  telephone  receiver  and 
battery  cell  are  surprising.  The  ticking  of  a  watch  or  the  fall  of  a  feather  is  heard  with  remark¬ 
able  distinctness . 


98-135 


KNOTT  BATTERY  CALL  TELEPHONE.  This  is  a  handsome,  well-constructed  instrument  with 
solid  back  transmitter,  double  pole  receiver,  vibrating  bell  and  call  button.  Guaranteed  to  give  full 
satisfaction  on  all  short  lines.  Readily  set  up  from  full  directions  which  accompany  the  instru¬ 
ment  . Each 

Per  pair 


SELENIUM  CELLS 


98-140  SELENIUM  CELL.  The  scientific 
importance  of  the  Selenium  Cell 
has  been  recognized  since  the 
work  of  Bell  and  Ruhmer.  It  was 
not,  however,  until  recently  that 
its  possibilities  in  the  commercial 
field  were  fully  realized.  Many 
experimenters  now  agree  that  it  is 
through  the  medium  of  the  Seleni¬ 
um  Cell  that  the  “seeing”  telephone 
may  eventually  become  a  reality. 
In  our  work  with  Selenium  we  have 
discovered  a  most  satisfactory 
method  of  attaching  the  material 
to  the  metal  backing  and  im¬ 
proved  methods  of  annealing  are 
employed.  The  object  has  been  to 
obtain  a  permanent  surface  and 
large  area  for  the  light  to  act  upon 
and  an  area  which  will  give  as  low 
initial  electrical  resistance  as  possi¬ 
ble. 

This  Selenium  Cell  is  extremely  sensitive  to  light,  dropping  in  resistance  many  thousands  of  ohms 
when  illuminated  by  a  light  of  average  intensity.  Connected  in  series  with  a  relay  and  battery,  it 
will  cause  the  relay  circuit  to  be  closed  when  the  cell  is  illuminated.  If  a  screen  be  interposed  be¬ 
tween  the  light  and  the  cell,  the  relay  circuit  will  be  immediately  opened.  A  telephone  receiver 
connected  in  series  with  the  Selenium  Cell  and  a  suitable  battery  will  cause  fluctuations  in  light 
to  be  detected.  For  example,  the  alternating  current  arc  gives  a  tone  depending  upon  the  fre¬ 
quency  of  the  current.  Changes  in  the  intensity  of*a  direct  current  arc  produced  by  superimposing 
on  it  a  telephone  current  are  audible. 

Selenium  Cell  unmounted,  surface  7  mm.  square . 

98-141  SELENIUM  CELL,  same  as  above,  but  with  rectangular  selenium  surface.  44  X  19  mm . 

98-142  MOUNTED  SELENIUM  CELL.  Consists  of  Selenium  Cell  No.  98-141  above  with  Adjustable 
Support  No.  98-146  . 

98-146  WNIVERSALLY  ADJUSTABLE  SUPPORT,  especially  designed  for  holding  the  mounted  Selenium 
Cell . 


$5.75 

4.25 

8.50 


$5.00 

11.50 

14.00 

2.50 


402 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MISCELLANEOUS  APPLICATIONS  OF 

ELECTRICITY 

ELECTROLYSIS  AND  ELECTRO-CHEMISTRY 


No.  99-6 


No.  99-10 


99-6  PACKARD’S  ELECTROLYSIS  APPARATUS.  We 

are  indebted  to  Mr.  John  C.  Packard  of  Brookline 
High  School  for  this  design.  In  simplicity  of  opera¬ 
tion  and  cleanliness,  it  excels  other  apparatus  de¬ 
signed  for  the  same  purpose.  There  are  no  parts 
which,  when  broken,  cannot  readily 
be  replaced.  Consists  of  two  special 
moulded  porcelain  bottle  rests 
which  are  designed  as  electrode  supports. 

These  bottle  and  electrode  supports  can  be 
used  close  together  or  apart  to  the  limit  of 
the  glass  tray.  In  use,  the  bottles  and  tray 
are  filled  to  a  point  covering  the  mouths, 
with  the  electrolyte.  When  current  is  con¬ 
nected,  action  immediately  begins. 

Complete  as  illustrated  with  glass  tray  .  .  .  $2.60 


No.  99-30 


30- 


m 


60= 


1=30 


=40 


=50 


99-20 


1 99-10  SIMPLE  ELECTROLYSIS  APPARATUS.  This  is  the  standard  form  with  sliding 
graduated  tubes  and  platinum  electrodes . 

99-16  THE  H-ELECTROLYSIS  OF  WATER  APPARATUS.  This  is  an  improved  type 
of  electrolysis  apparatus  so  designed  that  the  platinum  electrodes  may  easily  be 
replaced  by  those  of  carbon  or  copper.  In  addition  the  reservoir  tube  is  directly 
connected  without  bend  to  the  junction  tube  of  the  gas  tubes. 

This  type  is  ungraduated,  and  is  for  use  with  rubber  tubing  and  pinch-cocks. 

Complete  with  platinum  electrodes . 

99-20  THE  HOFFMAN’S  H-FORM  ELECTROLYSIS  OF  WATER  APPARATUS.  This 
design  has  the  same  improvements  as  the  one  above.  It,  however,  has  grad¬ 
uated  gas  tubes  provided  with  glass  stop-cocks  and  the  reservoir  is  globular 
shaped. 

Complete  with  platinum  electrodes . . . 

99-30^1, OSBORNE’S  IMPROVED  ELECTROLYSIS  APPARATUS.  This  design  has  the 
merit  of  efficient  use  in  study  of  principles  involved  in  electrolytic  dissociations. 
It  consists  of  an  H-tube  with  graduated  slide  tubes,  each  with  shot  valve.  By 
the  improved  construction  of  detachable  electrodes  the  platinum  electrodes  may 
be  readily  replaced  by  those  of  carbon  or  copper  as  illustrated.  With  a  glass  stop¬ 
per  plug  the  apparatus  is  set  up  as  a  conductivity  cell.  In  use  for  study  of  elec¬ 
trolysis  of  water  the  stopper  plug  is  replaced  by  the  bent  end  of  the  thistle  tube. 

Complete  as  illustrated . 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS 


403 


99-50  CARBON  ELECTRODES,  as  used  in  Nos.  99-15  and  99-30  . $0.66 

99-62  - ,  for  No.  99-20  .  75 

99-65  COPPER  ELECTRODES,  as  used  in  Nos.  99-16  and  99-30  . 55 

99-67  - ,  for  No.  99-20  . . 

99-60  PLATINUM  ELECTRODES,  as  used  in  Nos.  99-16  and  99-30  .  1.60 

99-62  - ,  for  No.  99-20  . •  3  qq 

99-76  TUBE  SUPPORT.  It  is  always  advisable  and  oftentimes  necessary  to  support  an  Electrolysis  of 
Water  Apparatus  during  experimentation.  Our  support  consists  of  a  neat  stand  with  clamp  and 
binding  posts .  155 

99-80  - ,  same  as  above,  but  smaller  in  size . .  1.40 


No.  99-100 


No.  99-105 


No.  99-195 


99-100  LANTERN  ELECTR9LYSIS  DEMONSTRATION  APPARATUS.  This  design  consists  of  a  U- 
shaped  trough  provided  with  a  hard  rubber  cover  with  binding  posts  to  which  are  connected  the 
platinum  electrodes.  This  form  will  not  leak  and  is  not  constructed  with  cumbersome  com¬ 
pressor  clamps. 

It  is  a  neatly  and  handsomely  finished  scientific  piece  of  apparatus . $4.76 

99-106  HYDROGEN  ABSORPTION  APPARATUS,  after  Hall’s  “Elements  of  Physics,”  Paragraph  50, 
for  showing  the  power  of  palladium  to  absorb  hydrogen.  Consists  of  a  palladium  and  a  platinum 
wire  mounted  parallel  in  a  solid  vulcanite  frame.  Binding  posts  supplied  for  connecting  to  a  source 
of  electric  current. 

The  frame  is  placed  upright  in  a  two  per  cent,  solution  of  sulphuric  acid  and  then  an  electric  current, 
strong  enough  to  decompose  the  solution,  is  connected  to  the  binding  posts.  It  will  be  noted  that 
there  is  a  visible  flow  of  oxygen  bubbles  from  the  platinum  wire,  but  no  hydrogen  bubbles  from 
the  palladium  wire.  Palladium,  when  cold,  absorbs  several  hundred  times  its  own  bulk  of  hy¬ 


drogen.  Without  beaker .  4.25 

MATERIAL  FOR  ELECTROPLATING 

99-110  SILVER  ANODE,  sheet  form . 1.25 

99-116  NICKEL  ANODE,  sheet  form . 75 

99-120  COPPER  ANODE,  sheet  form . 60 

COPPER  SULPHATE,  1  pound  bottle . 20 

AMMONIA  HYDROXIDE,  1  pound  bottle . 30 

AMMONIA  HYDROXIDE,  4  pound  bottle .  1.00 

POTASSIUM  CYANIDE,  1  pound  bottle . 60 

NICKEL  AND  AMMONIUM  SULPHATE,  1  pound  bottle . 60 

SILVER  CHLORIDE,  1  ounce  bottle .  .90 

POWDERED  PUMICE,  1  pound  package . 16 

ROUGE,  1  pound  package . 40 

TRIPOLI,  1  pound  package . 15 

POWDERED  EMERY,  1  pound  package . 16 

99-126  ROUGE  CLOTH,  especially  prepared .  .20 

99-130  CHAMOIS  SKIN . 66 


We  shall  be  very  glad  to  supply  the  formulae  on  request  for  making  solutions  for  silver,  nickel,  or  copper  electro¬ 
plating. 


99-170  ELECTROTYPING  LETTERS,  after  Turner  and  Hersey  (Experiment  E163);  also  used  in  Fuller 
and  Brownlee  (Experiment  71). 

Set  of  three  letters .  . $0.15 

99-195  ELECTROPLATING  OUTFIT  FOR  COPPER  PLATING,  consisting  of  jar,  special  clamp  cast¬ 
ings,  insulating  support  for  same,  two  copper  electrodes,  chemicals  and  complete  directions  for 
copper  plating .  1-65 


404 


L.  J£.  KNOTT  APPARATUS  CO.,  BOSTON 


f 


No.  99-200 


99-200  SIMPLE  ELECTRIC  FURNACE.  A  simple  practical  form  of  electric  furnace  that  will  be  found  of 
great  utility  in  the  teaching  of  the  electric  arc,  electric  furnace,  as  well  as  the  melting  and  com¬ 
bining  properties  of  many  elements.  The  construction  enables  a  clear  understanding  of  the  many 
principles  involved.  Its  open  construction  has  great  pedagogic  value. 

A  great  variety  of  experiments  may  be  conveniently  performed,  —  the  melting  of  platinum  or  like 
refractory  metals,  the  reduction  or  production  of  aluminum  or  carbides.  The  manufacture  of 
calcium  carbide  from  lime  and  sawdust  or  carbon  makes  a  striking  and  interesting  experiment. 

Complete  ready  for  use . $  .  .  .  . 


No.  99-360 

99-360  DEMONSTRATION  ARC  LAMP  WITH  REFLECTOR  for  use  with  any  strong  source  of  battery 
current,  but  excellent  for  use  with  our  No.  97-148  Gear  Drive  Hand  Power  Dynamo  in  demon¬ 
strating  the  principle  of  arc  lamps.  It  is  a  near  approach  to  the  automatic  form,  adjustment  by 
counterpoise  gravity  feed.  Quite  simple  in  form  and  of  open  construction  throughout.  A  simple 
reflector  attached  adds  greatly  to  the  effectiveness  of  the  design.  Complete  as  illustrated  .  .  . 


$26.00 


$3.30 


CATALOGUE  OF  PHYSICAL  INSTRUMENTS  405 


TOOLS 

We  list  below  various  tools  which  will  be  found  of  service  in  the  laboratory. 

200-10  AUGUR  BITS,  set  of  thirteen,  from  34  to  1  inch . $4.75 

200-15  BIT  BRACE . . 

200-20  BLOCK  PLANE  of  iron,  534  inches  long .  .45 

200-22  BREAST  DRILL.  Chuck  has  three  drawers  which  hold  round  shanked  bits  from  0  to  34  inch.  Drive 
wheel  5  inches  diameter.  Gearing  changeable  three  to  one.  Crank  adjustable  permitting  varia¬ 
tion  in  length  of  334  inches.  A  first-grade  tool  throughout .  3.80 

200—25  CHISEL,  best  Sheffield  steel,  one  inch  wide . 60 

200-30  CLAW  HAMMER,  first  quality  of  cast  steel,  weight  one  pound . 60 

200-35  CLAW  HAMMER,  nickel-plated,  ordinary  grade .  .48 

200-40  COLD  CHISEL,  34  inch . .  .20 

200-45  CORK  SCREW,  large  size .  16 

200-50  FILE,  flat,  8  inches  long .  .20 

200-55  FILE,  half  round,  8  inches  long . .20 

200-60  FILE,  round,  8  inches  long .  .18 

200-62  FILE,  triangular,  8  inches  long . •. .  .18 

200-66  GIMLET,  large  size,  5  inches  long .  .16 

200-70  HACK  SAW,  consisting  of  malleable  steel  frame  and  saw  blade  .  .  .  r .  .55 

200-76  HACK  SAW  BLADES,  8  inch,  to  fit  the  above  frame . Per  Dozen  .60 

200-77  HATCHET,  STEEL  CLAW,  best  forged  steel,  highly  polished  blade,  bronze  finish .  .76 

200-78  NIPPER,  end  cutting,  length  6  inches . 50 

200-80  OIL  STONE,  in  wooden  box,  7  inches  long .  .36 

200-82  PITCH  GAUGE,  “V”  threads,  22  pitches,  —  32,  34,  36,  38,  40,  42,  44,  46,  48,  50,  52,  54,  56,  58,  60, 

62,  64,  66,  68,  70,  72  and  74  threads  per  inch .  1.25 

200-85  PLIERS,  with  side  cutting  blade,  5  inches . 50 

200-86  PLIERS,  COMBINATION  SLIP  JOINT,  best  forged  steel,  natural  finish,  polished  jaws,  length 

634  inches .  . .  Each  .40 

200-88  PUNCH,  SPRING,  cast  steel,  first  quality,  full  polished . 35 

200-90  SAW,  CROSS-CUT,  26  inches  long .  1.60 

200-95  SAW,  RIP,  26  inches  long .  1.66 

200-100  SAW,  KEY-HOLE . 25 

200-105  SCREW  DRIVER,  instrument  size,  with  small  sharp  blade .  .20 

200-110  SCREW  DRIVER,  heavy,  8  inch .  .25 

200-115  SHEARS,  metal  cutting,  234  inch  blade . 76 

200-116  TAP  AND  DIE  SET.  Complete  with  stock  round  tap  wrench,  seven  adjustable  dies  and  seven  taps 
cutting  the  standard  threads  used  in  the  manufacture  of  our  apparatus :  —  %e,  Vsa,  %2,  %2, 10/s2,  x%4 
and  1%4.  In  polished  hardwood  case .  7.60 

200-117  TOOL  CABINET  for  wall.  Contains  18-inch  panel  saw,  smoothing  plane,  half  hatchet,  nail  hammer, 
bit  brace,  34  and  34-inch  bits,  5-inch  butt  chisel,  scraper,  awl  and  tool  set,  6-inch  flat-nose  plier, 

%2-inch  nail  set,  6-inch  try  square,  folding  boxwood  rule,  marking  gauge,  %0-inch  gimlet  bit,  8-inch 
mill  file  with  handle,  oil  stone,  carpenter’s  pencil,  oil  can,  can  of  glue,  2  sheets  of  sandpaper,  spool  of 
wire,  assorted  screws,  nails,  brads  and  tacks.  All  tools  of  the  highest  grade  of  steel.  Solid  oak 
cabinet  24  X  16  X  6  inches  deep,  doors  panelled,  antique  finish,  varnished  and  hand  rubbed,  with 
brass  padlock  with  two  keys . 21.00 

200-118  TOOL  HOLDER,  hollow  polished  cocobolo  handle,  containing  the  following  tools  warranted  the 
highest  grade  of  steel: —  two  sizes  firmer  chisels,  gouge,  three  sizes  of  screw  drivers,  gimlet,  key¬ 
hole  saw,  scriber,  reamer,  finely  finished  throughout .  1.10 

200-119  - ,  similar  to  above  but  smaller  and  containing  ten  tools,  as  commonly  supplied .  .40 

200-120  WRENCH  (MONKEY  WRENCH),  8  inches  long . 60 

FIRST  AID  CABINET 

No.  200-150 

Every  science  laboratory  should  be  equipped  to  render  first  aid  in  treating  cuts  and  burns.  That  we  may  ad¬ 
equately  meet  this  need,  we  have  made  up  a  first  aid  cabinet  containing  both  gauze  and  cotton  bandages, 
styptic  and  surgical  gauze,  court  plaster,  pins  and  the  ordinary  condiments  required  to  stop  bleeding 
and  for  the  proper  treatment  of  burns,  as  well  as  for  first  aid  treatment  in  case  of  poisoning.  Cabinet 
filled  complete . $2.60 


406 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


3600  AIR  TESTER,  DEWING’S,  for  testing  the  amount  of  CO2  in  the  air,  according  to  National  Biology 
Note-book  Sheet  P61.  Complete  with  Lime  Water,  Phenolphthalein,  Pipette,  Graduated  Flask, 

Graduated  Cylinder,  Graduated  Tube  and  Plunger,  with  full  directions . 

3602  AIR  TESTER,  after  Dr.  G.  WT.  Fitz,  for  the  accurate  determination  of  CO2. 

Consists  of  a  carefully  graduated  instrument,  set  of  Storage  Vials,  Graduated  Flask,  Graduated 
Pipette  and  full  set  of  directions.  A  most  satisfactory  piece  of  apparatus  for  an  accurate  determina¬ 
tion  of  the  amount  of  CO2  in  a  room.  With  reagents  in  neat  board  case . 

3604A  PHENOLPHTHALEIN  SOLUTION.  Quantity  sufficient  for  100  tests . 

3604B  LIME  WATER.  Quantity  sufficient  for  100  tests . 

3604C  GRADUATED  FLASK,  100  cc.,  for  above  apparatus . 

3604D  GRADUATED  PIPETTE,  1  cc.,  for  above  apparatus . 

3604E  GRADUATED  PIPETTE,  10  cc.,  for  above  apparatus . 

ALCOHOLOMETERS.  See  Nos.  6673A  and  6673B,  page  448. 

3606  SOLID  ALCOHOL  for  use  in  the  can  as  an  alcohol  stove.  This  alcohol  is  a  patented  product  moulded 
in  solid  form  in  a  slip  cover  can.  Always  ready  for  instant  use  by  removing  cover  and  lighting  con¬ 
tents  of  can.  An  intense  heat  is  at  once  generated  and  can  and  contents  can  be  used  to  as  good 
advantage  as  an  alcohol  lamp.  Flame  readily  extinguished  by  replacing  cover  upside  down  on  top 
of  can.  Capacity  of  can  3J£  ounces.  Will  burn  continuously  from  one  to  one  and  one-half  hours 
3610  ALUNDUM,  60  mesh,  for  protecting  the  bottoms  of  Alundum  Combustion  Boats  from  the  slagging 

effect  of  the  iron  oxide  during  the  combustion  of  the  sample  . Per  A-\b.  Bottle 

3612  ALUNDUM  CEMENT,  superior  to  other  mixtures  for  covering  wire  resistors  in  many  kinds  of  high 

temperature  electrical  apparatus  and  appliances  . Per  2-lb.  Bag 

3616  APRON,  chemical  and  water-proof,  48  inches  long,  36  inches  wide,  readily  adjusted  to  both  sexes  .  . 

OVERSLEEVES.  See  page  471. 

3620  AQUARIA  JARS,  ROUND,  heavy  colorless  glass. 

a  b  c 

Capacity,  quarts  2  4  8 

Size,  inches  6X6  7X7  9X9 

Each  $0.80  1.10  1.66 

3622  AQUARIUM  JAR,  RECTANGULAR,  heavy  colorless  glass,  capacity  2J4  gallons,  10J6  inches  long, 

6J£  inches  wide,  10J£  inches  high . 

3626  AQUARIA,  enameled  metal  frames,  glass  bottoms,  finished  in  dark  olive  green  with  gilt  decorations. 

abed 


3627 


3628 


Length,  inches 

12 

15 

18 

21 

Width,  inches 

8 

10 

12 

14 

Height,  inches 

7 

9 

11 

13 

Capacity,  gallons 

2'A 

5 

7 

12 

Each 

$4.00 

6.00 

7.00 

8.00 

AQUARIUM  TANK,  with  iron  frame  work  and  stone  base.  This  aquarium  must  not  be  confused  with 
those  where  the  light  is  blocked  from  the  ends  by  stone  slabs.  Our  tank  has  heavy  plate  glass  in  all  four 
sides,  these  glass  plates  being  held  by  substantial  iron  frames  locked  at  the  corners  by  iron  castings/! 

The  base  is  of  alberene  stone  1  inches  thick.  In  sealing  the  plates  water-tight,  we  use  a  cement  which 
we  compound  in  our  laboratories  and  which  we  guarantee  will  not  leak  nor  soften  by  action  of  water. 

Alberene  stone  base  measures  32  X  21  ins.  Dimensions  of  tank,  outside,  30 X  19  X  16  ins.  deep. 

Complete  with  standing  overflow  and  brass  gauze  separating  partition . 

SUPPORTING  AQUARIUM  TABLE.  We  have  frequently  supplied  a  table  support  for  the  above 
aquarium.  This  table  is  built  of  solid  oak  with  acid  proofed  built-up  maple  top.  It  is  equipped 
with  one  drawer  and  further  provided  with  a  special  long  goose-neck  water  supply  faucet. 

F.  O.  B.  Factory . 


$3.60 


3.00 

.40 

.30 

.40 

.10 

.20 


.10 

.60 

.70 

.80 


$4.00 


$48.00 


26.00 


CHEMISTRY  AND  BIOLOGY 


407 


1 


6875  ARSENIC  TUBES,  hard  glass. 

a  b 

Each  $0.06  .06 

Set  of  four . • 


c  d 

.06  .06 
. $0.22 


3540 


3541 


3543 


3545 

42-150 

42-162 

42-163 

42-160 

42-162 

42-163 

42-190 

42-175 

42-177 

42-178 

3550 


ASBESTOS 


Asbestos  is  fire  and  acid-proof  and  is,  therefore,  particularly  adapted  for  use  in  science  laboratories. 


ASBESTOS  BOARD,  40  X  40  inches. 


a  b 

Thickness,  inch  %2  V ie 

Per  Sheet  $0.42  .81 

ASBESTOS  BOARDS,  inch  thick. 

a  b 

Size,  inches  4X4  6X6 

Each  $0.03  .04 

ASBESTOS  BOARDS,  Ys 2  inch  thick. 

a  b 

Size,  inches  4X4  6X6 

Each  $0.02  .03 


ASBESTOS  WOOL,  long  selected  fibre.  Per  4-ounce  package 


1.20 


c 

12  X  12 

.16 


d 

%0 

2.20 


$1.10 


ASPIRATOR,  CHAPMAN’S,  of  brass,  334  inches  long,  34  inch  I.  P.  size  thread,  capacity  5  cubic 
feet  per  hour .  1.45 


HYDRANT  COUPLING  for  attaching  above  aspirator  to  a  %  inch  hose  bib  or  faucet .  .30 

HYDRANT  COUPLING  for  attaching  above  aspirator  to  a  smooth  faucet.  This  coupling  cannot 

leak  or  be  forced  off . 60 

ASPIRATOR,  CHAPMAN’S,  of  brass,  4%  inches  long,  34-inch  I.  P.  size  thread,  capacity  18  cubic 

feet  per  hour .  1.95 

HYDRANT  COUPLING  for  attaching  above  aspirator  to  a  34-inch  hose  bib  or  faucet .  .30 

HYDRANT  COUPLING  for  attaching  above  aspirator  to  a  smooth  faucet.  This  coupling  cannot 

leak  or  be  forced  off . 60 

ASPIRATOR,  MUENCKE’S,  of  glass,  834  inches  long.  This  is  a  convenient  demonstration  in¬ 
strument  as  all  parts  are  of  glass .  1.00 

ASPIRATOR,  RICHARDS’,  of  brass,  very  powerful,  7  inches  long,  %-incb  I.  P.  size  thread  ....  1.80 

HYDRANT  COUPLING  for  attaching  above  aspirator  to  a  34-inch  hose  bib  or  faucet . 30 

HYDRANT  COUPLING  for  attaching  above  aspirator  to  a  smooth  faucet.  This  coupling  will  not 

leak  and  cannot  be  forced  off .  .60 

ASPIRATOR,  HIGH  VACUUM,  more  powerful  than  preceding  and  uses  less  water,  34-inch  I.  P.  size 
thread.  Length,  434  inches .  1.66 


408 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  ) 


^^pr^CS^BOSTON.MASS. 


No.  3560 


No.  3563 


3560  HARCOURT  STUDENTS’  AUXANOMETER.  This  instrument  is  not  intended  for  precision  work, 
but  will  be  found  most  satisfactory  in  measuring  the  growth  of  plants  with  a  reasonable  degree  of 
accuracy  and  sensibility.  The  apparatus  as  shown  in  the  illustration  is  used  on  the  regulation  sup¬ 
port  stand  and  plant  growth  is  indicated  by  movement  of  a  pointer  over  a  graduated  arc.  Without 
Support  Stand . $3.25 

3563  BOVEE  PRECISION  AUXANOMETER,  an  invention  by  Dr.  W.  T.  Bo  vie  of  Harvard  University, 
for  recording  the  growth  of  plants.  For  classroom  or  out-of-door  use.  Will  indicate  growth  by  as 
small  as  0.1  millimeter. 

The  Bovie  Precision  Auxanometer  consists  essentially  of  a  device  which  is  carried  upward  as  the  plant 
grows. 

When  the  device  has  moved  a  certain  distance,  it  closes  an  electric  circuit  which  operates  the  record¬ 
ing  pen  of  the  chronograph.  This  arrangement  makes  it  possible  to  have  the  recording  mechanism  at 
any  desired  distance  from  the  plant  and  to  make  simultaneous  records  of  a  number  of  plants  or  of 
various  parts  of  the  same  plant. 

The  instrument  is  light,  compact  and  quickly  set  up  for  use  and,  as  the  force  of  gravity  is  not  utilized  for 
moving  any  of  its  parts,  it  may  be  set  at  any  angle  with  the  vertical  so  that  growth  in  any  direction 
may  be  measured  and  recorded.  Records  of  each  0.1  mm.  of  growth  can  be  made  and  the  instru¬ 
ment  will  be  found  reliable  in  or  out-of-doors.  The  experimental  model  was  run  by  Prof.  Bovie 
the  entire  summer  in  the  garden  exposed  to  the  weather,  the  brass  case  being  open  part  of  the  time 
so  that  the  internal  mechanism  was  exposed. 

Complete  specifications  furnished  upon  request. 

Furnished  in  plush-lined  polished  hardwood  box  with  hinged  cover 

BALANCES  AND  WEIGHTS.  See  pages  46  to  63. 


25.00 


CHEMISTRY  AND  BIOLOGY 


409 


No.  3675  No.  3677 


3570  BATHS,  SAND,  DEEP  HEMISPHERICAL,  of  sheet  iron. 

a  b  c 

Diameter,  inches  3  4  6 

Each  $0.10  .14  .27 


3572  BATHS,  SAND,  SHALLOW,  of  sheet  iron. 

a  b  c 

Diameter,  inches  3  4  6 

Each  $0.08  .10  .18 


d 

8 

.45 


d 

8 

.35 


3576  BATH,  SAND  or  HOT  PLATE.  Measures  6X8  inches. 

On  legs . $1.70 

3577  BATH,  SAND  or  HOT  PLATE,  RUEDORFF’S  with  ATTACHED  BURNER.  Of  cast  iron.  Meas¬ 

ures  11  X  7  inches,  with  three  rows  of  burners  that  are  adjustable  in  height . 14.25 


3579  PARAFFINE  BATH,  POLISHED  COPPER,  with  tubulations  for  thermometer,  gas  regulator  and 
three  test  tubes.  Dimensions,  7  inches  long,  Z%/i  inches  wide  and  3 34  inches  deep.  With  extra  sheet 
iron  bottom  and  iron  base  which  is  5  inches  high.  Provided  with  a  space  for  heating  slides  and  two 
nickel-plated  cups.  The  shallow  cup  is  234  inches  diameter,  24-inch  deep,  watch  glass  shape,  and 
the  deep  one  is  2%  inches  diameter  and  134  inches  deep .  9.75 


3580  PARAFFINE  BATH,  LEWIS’,  POLISHED  COPPER.  Temperature  of  this  bath  is  maintained  by  a 
constant  convectional  current.  The  heated  water  enters  the  bath  through  the  heating  tube,  lead¬ 
ing  from  the  heating  cylinder  into  the  side  of  the  bath  and  the  return  pipe  from  the  bottom  of  the 
bath  conveys  the  cooler  water  back  to  the  heating  cylinder.  The  stopcock  serves,  also,  to  regulate 
the  amount  of  hot  water,  thus  regulating  the  temperature.  Three  deep  cups,  1%  inches  diameter 
by  134  inches  deep,  tw'o  shallow  cups,  1J4  inches  diameter  by  %•  inch  deep,  four  test  tube  or  vial 
receptacles  and  one  opening  for  the  thermometer  are  provided . 19.76 


4io 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


WATER  BATHS 


The  water  baths  listed  below  are  of  polished  copper,  tin-lined,  most  carefully  made  throughout. 


No.  3682 


No.  3686 


No.  3687 


No.  3683 


No.  3690 


No.  3693 


3682  WATER  BATHS,  POLISHED  COPPER,  tin-lined,  with  concentric  rings  and  steam  cover. 

abed 
Diameter,  inches  5  6  8  10 

No.  of  Rings  4  5  7  8 

Each  $1.30  1.70  2.70  6.30 

3683  WATER  BATHS  WITH  STEAM  VALVE,  POLISHED  COPPER,  tin-lined,  most  excellent  and  eco¬ 

nomical. 

a  b  c 

Diameter,  inches  6  8  10 

No.  of  Rings  5  7  8 

Each  $4.90  6.86  8.26 

3686  WATER  BATH,  POLISHED  COPPER,  ON  TRIPOD,  tin-lined.  Seamless  body  with  concentric 

rings  and  cover,  steam  escape  and  extra  plate  perforated  for  test  tubes. 

a  b  c 

Diameter,  inches  5  6  8 

No.  of  Rings  4  5  7 

Each  $3.26  3.86  6.90 

3687  WATER  BATH,  POLISHED  COPPER,  tin-lined,  seamless  body,  with  concentric  rings  and  cover, 

steam  escape  and  extra  plate  perforated  for  test  tubes. 

a  b  c 

Diameter,  inches  5  6  8 

No.  of  Rings  4  5  7 

Each  $2.90  3.26  6.26 

3690  WATER  BATH,  FUNNEL  SHAPE,  POLISHED  COPPER,  tin-lined.  With  concentric  rings  and  con¬ 
stant  water  level.  Height  including  tripod,  8  inches. 

a  b 

Diameter,  inches  6  8 

No.  of  Rings  5  7 

Each  $3.90  4.86 

3693  WATER  BATH,  HOFFMAN’S,  of  heavy  polished  copper,  with  a  set  of  concentric  rings  and  plate  with 

five  holes  of  different  sizes,  each  with  cover.  With  constant  water  level.  Diameter  at  top,  8  inches  $13.76 


CHEMISTRY  AND  BIOLOGY 


3695  WATER  BATH,  GRIFFIN’S,  POLISHED  COPPER,  tin-lined  for  hot  filiations  and  evaporations. 

Provided  with  a  constant  water  level,  an  extra  sheet  iron  bottom  and  rests  on  four  detachable  legs. 
Size  13  X  7  X  5  inches  deep.  One  5-inch  hole  with  four  concentric  rings  and  steam  cover  and  one 


open  with  copper  funnel . $11.60 

3600  WATER  BATH,  ELECTRICALLY  HEATED,  POLISHED  COPPER,  tin-lined.  With  two  remova¬ 
ble  covers,  one  cover  with  two  5-inch  openings  and  concentric  rings,  the  other  with  thirty-six 
inch  holes  for  test  tubes.  Size  14J4  X  6J4  X  3  inches  deep.  Height  over  all  734  inches.  Provided 
with  automatic  cut-out  that  shuts  off  current  if  bath  is  allowed  to  run  dry . 32.50 

3606  WATER  BATH,  POLISHED  COPPER,  tin-lined,  with  concentric  rings  and  steam  cover.  Provided 

with  stopcock  and  Kekule’s  Water  Level  Regulator.  With  extra  sheet  iron  bottom,  and  supported 
by  four  detachable  legs.  Size  14  X  14  X  5  inches  deep.  Four  openings,  5  inches  in  diameter, 

with  rings  and  steam  cover . 17.00 

3606A  WATER  BATH,  STEAM,  POLISHED  COPPER,  tin-lined,  same  as  above,  but  arranged  with  coil 

to  be  heated  by  steam . 20.75 

3606B  WATER  BATH,  ELECTRIC,  POLISHED  COPPER,  tin-lined,  same  as  above,  but  arranged  for  elec¬ 
trical  heating . 39.26 

3607  WATER  BATH,  POLISHED  COPPER,  tin-lined,  with  concentric  rings  and  cover,  provided  with  stop¬ 

cock  and  Kekule’s  Water  Level  Regulator.  With  extra  sheet  iron  bottom  supported  by  four  de¬ 
tachable  legs.  Size  23  X  13J4  X  5  inches  deep.  Seven  openings,  three  of  6  inches  diameter  and 

four  of  4  inches  diameter  with  concentric  rings  and  steam  cover . 23.50 

3607A  WATER  BATH,  STEAM,  POLISHED  COPPER,  tin-lined,  same  as  above,  but  arranged  with  coil  to 

be  heated  by  steam . 28.26 

3607B  WATER  BATH,  ELECTRIC,  POLISHED  COPPER,  tin-lined,  same  as  above,  but  arranged  for  elec¬ 
trical  heating . 54.00 

3610  WATER  BATH,  POLISHED  COPPER,  tin-lined,  with  concentric  rings  and  steam  cover.  Provided 
with  stopcock  and  Kekule’s  Water  Level  Regulator.  With  extra  sheet  iron  bottom  and  supported 
by  four  detachable  legs.  Size  28  X  14  X  5  inches  deep,  eight  openings  5  inches  in  diameter  with 

rings  and  steam  cover . 29.60 

3610A  WATER  BATH,  STEAM,  POLISHED  COPPER,  tin-lined,  same  as  above,  but  arranged  with  coil  to 

be  heated  by  steam . . . . 34.25 

3610B  WATER  BATH,  ELECTRIC,  POLISHED  COPPER,  tin-lined,  same  as  above,  but  arranged  for  elec¬ 
trical  heating . ' . 58.50 

BATTERIES.  See  pages  320  to  325. 

BATTERY  JARS.  See  pages  326  and  461. 

3616  BEADS,  GLASS,  hollow,  for  filtering  and  drying  gases  by  means  of  acid . Per  pound  .96 


412 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


BEAKERS 


Our  line  of  Beakers  has  been  selected  with  unusual  care.  We  are  confident  that  our  customers  will  find  not  only 
the  kind  but  also  the  quality  desired. 

We  have  given  special  attention  to  our  Glass  Beakers.  We  offer  an  exceptionally  high  grade  glass  in  our  Har- 
court  Line  and,  quality  considered,  we  feel  that  this  line  cannot  be  excelled  at  even  a  much  higher  cost. 


L-r 'KMOfiT  APkftVAfUS  CO 

ROiT-jw  .MAOS 


3625  BEAKERS,  HARCOURT  GLASS,  low,  wide  Griffin  form,  with  lip. 


a 

b 

c  d 

e 

f 

g 

h 

No. 

1 

2 

3  4 

5 

6 

7 

8 

Capacity,  cc. 

75 

100 

200  300 

400 

600 

800 

1000 

Each 

$0.10 

.13 

.16  .19 

.24 

.30 

.35 

.45 

BEAKERS,  HARCOURT  GLASS, 

same  as  above,  but  nested  as  follows: 

a 

b 

c 

d 

e 

f 

No.  in  Nest 

3 

4 

5 

6 

7 

8 

Size  No. 

1-3 

2-5 

1-5 

1-6 

1-7 

1-8 

Capacity,  cc. 

75-200 

100-400 

75-400 

75-600 

75-800 

75-1000 

Per  Nest 

$0.39 

.72 

.82 

1.12 

1.47 

1.92 

3628  BEAKERS,  “PYREX”  GLASS.  (See  index,  “Pyrex  Glassware”  for  characteristics.)  Griffin  low 

form,  with  lip. 

a  bcdefgh  i  jk  1 
Capacity,  cc.  50  100  150  250  400  600  800  1000  1300  1500  2000  2500 

Each  $0.13  .15  .17  .19  .27  .33  .38  .64  .65  .73  .98  1.13 

3629  BEAKERS,  “PYREX”  GLASS,  same  as  above,  but  nested  as  follows: 


a 

b 

c 

d 

e 

f 

No.  in  Nest 

3 

4 

5 

6 

7 

8 

Capacity,  cc. 

50-150 

50-250 

50-400 

50-600 

50-800 

50-1000 

Per  Nest 

$0.45 

.64 

.91 

1.24 

1.62 

2.16 

3631 

BEAKERS,  HARCOURT  GLASS, 

wide,  usual  form,  without  lip. 

a  b 

c 

d 

e 

f 

g 

h 

Size  No. 

1  2 

3 

4 

5 

6 

7 

8 

Capacity,  cc. 

75  100  200 

300 

400 

600 

800 

1000 

Each 

$0.10  .13  .16 

.19 

.24 

.30 

.35 

.46 

3632 

BEAKERS,  HARCOURT  GLASS, 

same  as  above,  but  nested  as  follows: 

a 

b 

c 

d 

e 

f 

No.  in  Nest 

3 

4 

5 

6 

7 

8 

Size  No. 

1-3 

2-5 

1-5 

1-6 

1-7 

1-8 

Capacity,  cc. 

75-200 

100-400 

75-400 

75-600 

75-800 

75-1000 

Per  Nest 

$0.39 

.72 

.82 

1.12 

1.47 

1.92 

3635 

BEAKER,  VASE  SHAPE,  ON  ROOT,  for  use 

on  lecture  desk  for  a  large  class  of 

chemical  experiments. 

Capacity  350  cc 

.  .  $0.60 

No.  3635 


CHEMISTRY  AND  BIOLOGY 


413 


3638 


3640 


3646 


3660 


3660 


3661 

3663 

3664 

3666 

3667 
3676 

3676, 


BEAKERS,  ALUMINUM,  Griffin  form,  with  lip. 

a  b  c 

Capacity,  cc.  250  500  1000 

Each  $0.66  1.00  1.60 

BEAKERS,  SPUN  COPPER,  polished,  Griffin  form,  with  lip. 

a  b  c 

Capacity,  cc.  250  500  1000 

Each  $0.66  .90  1.60 


BEAKERS,  PORCELAIN,  without  lip,  glazed  inside  and  outside,  extensively  used  in  testing 


stuffs,  etc. 

a 

b 

c 

Capacity,  cc. 

340 

580 

970 

Height,  inches 

4  H 

5  Vi 

6  Vs 

Diameter,  inches 

3 

3% 

4 

Each 

$1.00 

1.26 

1.76 

of  dye 


BEAKERS,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware”  for  characteristics.)  With  lip. 


Capacity,  cc. 
Each 


a  b 

50  100 

$0.90  1.00 


c  d 

150  200 

1.10  1.20 


e  f 

250  400 

1.46  1.70 


g 

500 

1.96 


h 

600 

2.20 


800 

2.66 


BELL  GLASSES.  See  page  164. 


BIRDS 

BIOLOGY  AND  NATURE  STUDY 


We  have  made  arrangements  with  a  leading  taxidermist  so  that  we  carry  the  following: 


COLLECTION  OF  MOUNTED  BIRDS  FOR  SCHOOL  USE.  Contains  thirty 
of  our  common  species  representing  the  common  orders.  It  includes  *Grebe, 

Tern,  Teal,  ’Heron,  Rail,  ’Sandpiper,  *Hawk,  Owl,  Kingfisher,  ’Woodpecker, 
’Kingbird,  Phoebe,  ’Bluejay,  ’Crow,  Cowbird,  ’Blackbird,  Meadow  Lark, 
Goldfinch,  Native  and  English  ’Sparrow,  Towhee,  Scarlet  Tanager,  ’Barn- 
Swallow,  Red-Eyed  Vireo,  ’Common  Warbler,  Catbird,  House  Wren,  Chicka¬ 
dee,  ’American  Robin,  ’Bluebird . $74.00 


SKINS  of  the  above,  unmounted . 36.00 

FIFTEEN  COMMON  SPECIES  representing  those  starred  in  above  list  .  .  .  38.00 

SKINS,  unmounted . 18.00 

COLLECTION  OF  EGGS,  corresponding  to  above  collection  (in  a  few  cases 

not  identical  with  it  in  species) .  6.40 

COLLECTION  OF  EGGS,  representing  those  starred  in  above  list .  2.76 

BLAST  APPARATUS,  RICHARDS’,  for  use  where  water  pressure  is  available, 
in  obtaining  either  blast  or  vacuum.  Desirable  for  quick  filtering  and  oper¬ 
ating  blast  lamp.  Complete  with  one  Aspirator .  9.76 

- ,  with  two  Aspirators . 12.00 


No.  3676 


414 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


3686  BLAST  LAMP,  GASOLINE,  pint  capacity,  giving  a  small  hot  flame,  generating  its  own  gas.  With 

holder  with  cork-lined  cap  on  side  of  the  body  for  holding  cleaner  wire  and  nozzle  when  not  in  use. 

Will  burn  constantly  for  about  three  hours  with  one  filling . $1.60 

3687  BLAST  LAMP,  GASOLINE,  one  pint  capacity,  giving  an  intensely  hot  blue  flame  which  can  be  regu¬ 

lated  to  a  small  pointed  flame  or  brush  flame  as  desired.  Of  seamless  drawn  brass  and  fitted  with  an 

automatic  brass  pump .  4.60 

For  other  BLAST  LAMPS  and  BURNERS,  see  pages  200-202. 

BLOWERS,  FOOT,  for  supplying  a  blast  of  air  for  lamps,  blowpipes,  etc.  A  rubber  disc  forms  the 
air  reservoir  and  equalizes  the  pressure  by  its  elasticity.  By  increasing  the  number  of  discs  a  greater 
air  pressure  is  obtained. 

We  list  two  styles,  one  with  air  reservoir  above,  the  other  with  legs  and  air  reservoir  below. 

3696  BLOWER,  FOOT,  air  reservoir  above,  diameter  of  reservoir  7J4  inches,  pressure  of  blast  per  inch 
one  pound,  cubic  feet  of  air  per  hour  190. 

With  single  disc .  6.00 

3696  - ,  diameter  of  reservoir  9  inches,  pressure  of  blast  per  inch  pounds,  cubic  feet  of  air  per  hour 

330.  With  double  disc .  8.16 

3697  - ,  diameter  of  reservoir  11  inches,  pressure  of  blast  per  inch  1%  pounds,  cubic  feet  of  air  per 

hour  625.  With  three  discs . 12.90 

3699  BLOWER,  FOOT,  with  legs,  air  reservoir  below.  Diameter  of  reservoir  7}^  inches,  pressure  of  blast 

per  inch  one  pound,  cubic  feet  of  air  per  hour  190.  With  single  disc .  6.86 

3700  - ,  diameter  of  reservoir  9  inches,  pressure  of  blast  per  inch  1J^  pounds,  cubic  feet  of  air  per  hour 

330.  With  double  disc . . . .  9.36 

3701  - ,  diameter  of  reservoir  11  inches,  pressure  of  blast  per  inch  pounds,  cubic  feet  of  air  per  hour 

625.  With  three  discs . 13.80 

3702  RUBBER  DISC,  made  of  the  best  quality  para  rubber,  steam  cured.  9J4  inches  diameter,  for  use  with 

Blowers  Nos.  3696  and  3699  . Each  .96 

3702A  ,  same  as  above,  but  11 J4  inches  diameter,  for  use  on  Blowers  Nos.  3696  and  3700  . Each  1.36 

3702B  ,  same  as  above,  but  14^  inches  diameter,  for  use  on  Blowers  Nos.  3697  and  3701  . Each  1.96 

3702C  BLOWER  NETS,  as  used  on  above  Blowers . Each  .46 


3710 

BLOWPIPES,  of  brass,  plain. 

a 

b 

Length,  inches 

8 

10 

Each 

$0.22 

.28 

3711 

BLOWPIPES,  of  brass,  with  bulb. 

a 

b 

Length,  inches 

8 

10 

Each 

$0.36 

.42 

3716  BLOWPIPE  MOUTH  PIECE,  trumpet  shape,  hard  rubber,  \%  inches  diameter . $0.40 

3716A  BLOWPIPE  MOUTH  PIECE,  ordinary  form,  of  close  grained  hard  wood,  1  inches  long . 12 

3720  BLOWPIPE,  AUTOMATIC  BRAZING,  nickel-plated,  for  light  soldering.  Length  10  inches  .  .  .  2.46 

3722  BLOWPIPE,  AUTOMATIC  BRAZING,  with  pilot  light.  Small  size,  of  brass,  with  two  stopcocks, 

%5-inch  air  tube  and  %-inch  gas  tube.  Length  11  inches .  1.96 

3724  BLOWPIPE,  AUTOMATIC  BRAZING,  for  general  work.  Of  brass,  with  two  stopcocks,  %-inch  air  pf« 

tube  and  5^-inch  gas  tube.  Length  16  inches .  4.40 


CHEMISTRY  AND  BIOLOGY 


415 


3726  BLOWPIPES,  GLASS  BLOWERS’  FIRES  OR  BURNERS.  Two  required,  one  mounted  opposite  to 
other.  For  use  with  foot  blowers  or  other  forms  of  blast.  Each  with  three  burners.  Mounted 

as  illustrated  on  stand.  Per  set  of  two  . .  $14.76 

BONE  CUTTING  FORCEPS,  see  page  433. 

BONE  SAW.  See  page  433. 

BOTANICAL  MOUNTS.  See  SPECIMEN  MOUNTS,  page  480. 

BOTANICAL  PRESS.  See  PLANT  PRESS,  page  472. 


3736 


3736 


3737 


3738 


3740 


3742 

3746 

3747 
3749 

3761 

3763 


b 

2 

.04 

b 

2 

.04 


No.  3737 

BOTTLES,  prescription,  narrow  mouth.  a 

Capacity,  ounces  1 

Each  $0.03 

BOTTLES,  prescription,  wide  mouth.  a 

Capacity,  ounces  1 

Each  $0.03 

BOTTLES,  tincture,  narrow  mouth,  with  ground  glass  stopper. 

a  b  c 

Capacity,  ounces  12  4 

Each  $0.09  .10  .12 

BOTTLES,  salt  mouth,  wide  mouth  with  ground  glass  stopper. 

a  b  c 

Capacity,  ounces  12  4 

Each  $0.09  .10  .12 

BOTTLES,  ACID  or  STORAGE,  with  ground  glass  stoppers. 
Capacity,  pints 
Each 


No.  3738 


c 

4 

.06 

c 

4 

.06 


d 

8 

.09 

d 

8 

.09 


e 

16 

.14 

e 

16 

.14 


d 

8 

.16 

d 

8 

.16 

a 

1 

$0.16 


e 

16 

.22 

e 

16 

.22 

b 

5 

.30 


f 

32 

.20 

f 

32 

.20 

f 

32 

.36 

f 

32 

.36 


3746 


No.  3747 


3749 


No.  3761 


No.  3763 


BOTTLE,  ASPIRATOR,  with  tubulature  for  rubber  tubing,  capacity  32  ounces . $1.26 

BOTTLE,  BALSAM  or  DROPPING,  triangular  shaped  ground  glass  stopper,  drawn  to  a  point, 

ground  glass  cap.  Capacity  1J4  ounces . 

BOTTLE,  BALSAM  or  DROPPING,  with  ground  glass  cap  and  glass  rod.  Capacity  2  ounces  .  .  . 
BOTTLE,  DROPPING,  bulb  pipette,  ground  into  the  neck,  forms  an  air-tight  container.  Capacity  one 

ounce  . 

BOTTLE,  DROPPING  (COBALT  BOTTLE),  with  ball  top,  pipette  ground  in.  Capacity  one  ounce 
BOTTLES,  DROPPING,  with  grooves  in  neck  and  in  stopper.  When  the  grooves  coincide,  the  con¬ 
tents  may  be  poured  out  drop  by  drop.  A  quarter  turn  of  the  stopper  closes  the  bottle  air-tight. 

a  b 

Capacity,  ounces  1  2 

Each  $0.26  .30 


.35 

.48 

.36 

.48 


4i6 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


Vitrified  Labels 
Transparent  Letters 


Capacity 
Height,  inches 
Per  dozen 


REAGENT  BOTTLES 

With  Indestructible  Vitrified  Labels — With  Raised  Ground  Glass  Labels — 

Transparent  Letters. 

Both  types  of  Reagent  Bottles  listed  are  free  from  lead,  zinc  or  other  me¬ 
tallic  flux.  They  are  uniform  in  shape  and  the  different  capacities  are  uniform 
in  height.  The  Reagent  Bottles  with  Raised  Ground  Glass  Labels  have  long 
been  in  use  and  can,  therefore,  be  called  the  Standard  Type.  The  variety  of 
stock  labels,  however,  is  limited  and  many  science  laboratories  have  required 
us  to  furnish  bottles  which  will  have  labels  covering  chemicals  and  reagents 
complete  as  used  in  science  laboratories.  Our  Reagent  Bottles  with  Indestructi¬ 
ble  Vitrified  Labels  meet  this  demand. 

REAGENT  BOTTLES  WITH  RAISED  GROUND  GLASS  LABELS.  ORDER 
BY  CATALOGUE  NUMBERS  in  the  following  listings.  When  no  number  is  listed 
the  raised  ground  glass  label  cannot  be  obtained,  but  to  order,  and  at  an  extra 
price,  the  same  shape  and  size  may  be  obtained  with  label  engraved  on  the  bottle. 


Ounce 

Ounce ‘(W7ide  Mouth) 

Pint 

J4  Pint  (Wide  Mouth) 

Vi  Pint 

3^4 

5^4 

4  Vs 

6V2 

$1.35 

1.48 

1.96 

2.15 

2.66 

Raised  Ground 
Glass  Labels 

Pint  Quart 

7  H  9'A 

3.65  4.86 


REAGENT  BOTTLES  WITH  INDESTRUCTIBLE  VITRIFIED  LABELS 

These  bottles  have  a  smooth  white  background  against  which  the  transparent  letters  and  symbols  are  clearly 
defined.  Although  higher  in  cost  than  Reagent  Bottles  above  described,  these  bottles  greatly  enhance  the  appear¬ 
ance  of  the  equipment  and  have  the  advantage  that  stock  labels  for  practically  all  the  chemicals  and  reagents  used 
in  science  laboratories  may  be  obtained.  ORDER  BY  CATALOGUE  NUMBERS,  in  the  following  listings.  Where 
no  number  is  listed,  bottles  with  labels  not  on  the  list  can  be  obtained  but  at  an  extra  price  and  on  order  only. 
Capacity  M  Pint  34  Pint  (Wide  Mouth)  34  Pint  Pint  Quart 

Height,  inches  534  534  634  7 34  934 

Per  Dozen  $5.76  6.76  6.80  7.26  8.90 

Suggestive  Equipments  for  Students’  Desks,  General  Laboratory  Use  and  Stock  May  Be  Obtained  on  Application. 


SS^ 

3  w 

°  c 

’"O, 


V* 

CO  0) 

S3 

Oti 

csj  2 

w<5 


j 

o 

m 

2 

>< 

C/3 


WITH  INDESTRUCTIBLE  VITRIFIED  LABELS 
J 

a^ss 

0-5  Cd^  0-5 

n  g  oo a. 

* 

401  402  801  1601  3201 

403  404  803  1603  3203 

405  406  805  1605  3205 

409  410  809  1609  3209 

413  414  813  1613  3213 

417  418  817  1617  3217 

—  -  819  1619  - 

-  821  1621  3221 

423  424  823  1623  3223 

427  428  827  1627  3227 

-  —  829  1629  3229 


WITH  RAISED  GROUND  GLASS  LABELS 


NAME 


J 

O 

ffl 

S 

>- 

co 


e 

3 

O 


as 

H 

a 

o  »> 

n 

ao 

a 


437 

438 

837 

1637 

3237 

(NHi)sS . 

441 

442 

841 

1641 

3241 

NH«CNS . 

— 

— 

845 

1645 

3245 

SbCl6 . 

449 

450 

849 

1649 

3249 

BaCl2 . 

451 

452 

851 

1651 

3251 

Ba(OHl2 . 

453 

454 

853 

1653 

3253 

Ba(N03)2 . 

— 

— 

855 

1655 

3255 

C6H6 . 

457 

458 

857 

1657 

3257 

461 

462 

861 

1661 

3261 

Br . 

463 

464 

863 

1663 

3263 

CaCh . 

— 

— 

865 

1665 

3265 

CaCl2 . 

467 

468 

867 

1667 

3267 

Ca(OH)s . 

R71 

lfi7l 

3971 

473 

474 

873 

1673 

3273 

CS2 . 

875 

1675 

3275 

477 

478 

877 

1677 

3277 

Cl . 

— 

— 

879 

1679 

3279 

CHCI3 . 

481 

482 

— 

— 

— 

H3C6H5O7 . 

483 

484 

883 

1683 

3283 

Co(NOs)2 . 

485 

486 

885 

1685 

3285 

— 

488 

— 

— 

— 

Cu . 

489 

490 

889 

1689 

3289 

CuS04 . 

491 

492 

891 

1691 

3291 

493 

494 

893 

1693 

3293 

— 

— 

895 

1695 

— 

HC2H3O2 . Acetic  Acid . 

C2HsOH . Alcohol . 

NHj . Ammonia . 

(NH4)2C03 . Ammonium  Carbonate . 

NH4CI . Ammonium  Chloride . 

NH4OH . Ammonium  Hydroxide . 

. . Ammonium  Hydroxide.  Cone.. 

. . Ammonium  Hydroxide,  Dil.. . . 

(NH4)eMo7024  . Ammonium  Molybdate . 

(NH4)2C20« . Ammonium  Oxalate . 

(NH4)2HP04 . Ammonium  Phosphate . 

. . Ammonium  Sodium  Phosphate 

Ammonium  Sulphate  . 


Ammonium  Sulphydrate  . 


Barium  Carbonate . 


Blank . 
Borax . 


Calcium  Sulphate  . . 
Carbon  Bisulphide . 


Carbon  Tetrachloride. 


Cochineal. 


Esbach's  Solution . 

Ether . 

Ethyl  Alcohol .... 


HC2H3O2 . 

C2H5OH . 

NH3 . 

(NH4)SC03.... 

NH4CI . 

NH4OH . 

.NiLOH+Aq ; ; 

(NH4)6Mo7024. -  - 

(NH4)2C204  .  .  . - 

(NH4)2HP04  . . - R130 

NaNH4HP04.  . - R132 

(NH4)2S04  ....  - - 

(NH4)2S . 

NH4CNS . 

•NH4HS . 

BaCOs . 

BaCl2 . 

Ba(OH)2 . 

Ba(N03)2 . 

- R157  R158 

Na3B407  . .  R160 

CaCl2 . 

CaCb . 

Ca(OH)2.  .  .  . 

CaS04 ...... 

CS2 . 

CHCI3.  .  .  .  - 

Co(NOj)2'.  ’ .’ .' .  R183 - 

Cu . ."  ! .’ - R188 

CUSO4 . .  . 

(C2H5)20 . .  . 


-3 

O.S 

3.  a. 


R401 

R403 

R405 

R409 

R413 

R417 


R423 

R427 


►J 

SJ 

tfl 

o  a> 

S  c 

*5 


eS 

3*. 

o.s 

00  0. 


R801 

R803 

R805 

R809 

R813 


o*. 


to  0) 

si 

(N  « 
W  3 
O 


R817  R1617 


R823 

R827 


R1621 


R437 

R441 

R443 

R447 

R449 

R451 

R453 

R457 

R461 

R463 

R465 

R467 

R469 


R434 


R837  R1637 


R849  R1649 


R458 

R460 


R857  R1657 


R867  R1667 
-  R1669 


R473 

R479 

R485 

R489 

R493 


R1693 


CHEMISTRY  AND  BIOLOGY 


417 


WITH  INDESTRUCTIBLE  VITRIFIED  LABELS 


WITH  RAISED  GROUND  GLASS  LABELS 


g^o-s 
S  ied.  a'-' 
3"  3  -w 

0.3  o.S 


w  ^ 

wj 
o'-* 
c> 


W 

Q  i>  00 

o 


°r 

CO  C 


IB 

w, 

<N  g 
m  3 
O 


W 

O 

ra 

5 

>< 

CO 


511 

512 

517 

518 

521 

522 

525 

526 

529 

530 

533 

534 

535 

536 

537 

538 

541 

542 

— 

546 

549 

550 

551 

552 

553 

554 

555 

556 

561 

562 

563 

564 

565 

566 

569 

570 

575 

576 

581 

582 

583 

584 

585 

586 

587 

588 

591 

592 

593 

594 

597 

598 

599 

600 

601 

602 

603 

604 

605 

606 

607 

608 

609 

610 

611 

612 

613 

614 

615 

616 

617 

618 

619 

620 

621 

622 

623 

624 

627 

628 

631 

632 

633 

634 

635 

636 

641 

642 

643 

644 

647 

648 

651 

652 

— 

654 

655 

656 

— 

662 

663 

664 

zz 

666 

897 

1697 

3297 

899 

1699 

3299 

901 

1701 

3301 

903 

1703 

3303 

905 

1705 

3305 

907 

1707 

3307 

909 

1709 

3309 

911 

1711 

3311 

915 

1715 

3315 

917 

1717 

3317 

921 

1721 

3321 

923 

1723 

3323 

925 

1725 

3325 

929 

931 

1729 

3329 

933 

1733 

3333 

935 

1735 

3335 

937 

1737 

3337 

939 

1739 

3339 

941 

1741 

3341 

•  943 

1743 

3343 

■  947 

1747 

3347 

1  949 

1749 

3349 

:  951 

1751 

3351 

:  953 

1753 

3353 

i  955 

1755 

3355 

•  957 

1757 

3357 

959 

1759 

3359 

!  961 

1761 

3361 

:  963 

1763 

3363 

i  965 

1765 

3365 

967 

1767 

3367 

1  969 
971 

1769 

1771 

3369 

■  973 

1773 

3373 

975 

1775 

3375 

•  977 

1777 

3377 

979 

1779 

3379 

:  983 

1783 

3383 

985 

1785 

3385 

987 

1787 

3387 

989 

1789 

3389 

991 

1791 

3391 

993 

1793 

3393 

995 

1795 

3395 

999 

1799 

3399 

1001 

1801 

3401 

1003 

1803 

3403 

1005 

1805 

3405 

1007 

1807 

3407 

1009 

1809 

3409 

1011 

1811 

3411 

1013 

1813 

3413 

1017 

1817 

3417 

1021 

1821 

3421 

1023 

1823 

3423 

1027 

1827 

3427 

1031 

1831 

3431 

1033 

1833 

3433 

1039 

1839 

3439 

1041 

1841 

3441 

1045 

1845 

3445 

1047 

1847 

3447 

1051 

1851 

3451 

1055 

1855 

3455 

1057 

1857 

3457 

1063 

1863 

3463 

NAME 


.  Fehling’s  Alkaline  Solution. 
.  Fehling’s  Copper  Solution.  . 
.  Fehling’s  Solution . 


W 

O 

m 

S 

;* 

to 


c 

3 

o 


a 

H 

p 

O  <u 

WO 

Q 


W  vao 
4JX 
o  r_> 

a 

O.S 


i-3 

wx 

Si 

§s 

Qg 

*1 


(DV* 

C  — * 
3  4-» 

O.S 
00  a. 


§$ 
co  G 


co  o 

O  4-» 

«d 

3 

a 


■  Fe2Cl6. 
.FeS04. 
.FeS... 


.  Formalin . 

.  Glycerine . . 

.  Gold  Chloride . AuCl3 . 


R501 

- R503  - 

R206  R505  R506  R905 
R208 


R1705 


.  R213 


.  Hydrochloric  Acid . HC1  . 

.Hydrochloric  Acid,  Cone . HC1  . 

.  Hydrochloric  Acid,  Dil . HC1  . 


.  Hypophosphoric  Acid,  Dil..  .  . 
.  Indigo  Solution . 


.Pb(C2H302)2. 


. Litmus  Paper . 

. Litmus  Solution. ..  . 

. Magnesia  Mixture  . 


•  MgS04. 


•  HgClj.  . 
■  HgNOs- 


.  Methyl  Orange. . . 
.  Millon's  Reagent . 

.  Nessler’s  Solution. 


.  Nitric  Acid . HNO3. 

.  Nitric  Acid,  Cone . HNO3. 

.  Nitric  Acid,  Dil . HNO3. 

.  Nitro  Hydrochloric  Acid . . 

.  Nitro  Hydrochloric  Acid,  Dil... - 

.Nitro  Sulphuric  Acid . . 

.  Oil  Turpentine . 


.  h2c2o4. 


.  Phenolphthalein . 

.  Phosphoric  Acid,  Dil . 


PtCU. 


.  R291 


KBr . Potassium  Bromide  . 


k2co3. 


KNO3 . Potassium  Nitrate.  . 

KNaC4H406+4H20  ..Potassium  Sodium  T 
K2S04 . Potassium  Sulphate. 


.KI.... 

.KNO3. 

.k2so4. 


R302 

R306 


R316 


.  Silver  Sulphate . Ag2S04 . 


.  R323 


.Sodium  Bitartrate . NaHC4H406  . 


•  R330 


633  634  1033  1833  3433  Na2C03 . Sodium  Carbonate . Na2COs. 

NaC103 . Sodium  Chlorate . . 

. . Sodium  Cobaltic  Nitrite . . 


641  642  1041  1841  3441  NaOH . Sodium  Hydroxide . NaOH. 

NaPH202 . Sodium  Hypophosphite. 


.  Sodium  Nitrate . NaN03. 


.  Sodium  Thiosulphate . Na2S203. 

.  Stannous  Chloride . SnCl2. .  . 

.  Starch . . . 

.  . .  . . Sulphuric  Acid . .....H2S04.. 

1057  1857  3457  H^S04 . Sulphuric  Acid,  Dil . H2S04.. 

.  Sulphuric  Acid,  Cone . H2S04  .  . 

Test  Paper . . . 

Turmeric . . 

Zn . Zinc. . . . Zn. 


R346 


R354 


R517 

R519 

R1717 

R1719 

— 

R919 

R921 

R3319 

R3312 

R525 

R529 

R929 

R533 

R537 

R541 

R941 

R547 

R549 

R551 

R555 

R557 

R559 

R561 

R955 

R565 

R569 

R571 

R1769 

R1771 

— 

R971 

R973 

R3371 

R3373 

R583 

R585 

R587 

R591 

R593 

R599 

R603 

R606 

R607 
R609 
R61 1 
R613 

RlOll 

R1811 

R616 

R619 

R621 

R623 

R625 

R627 

R1023 

R633 

R634 

R1033 

R637 

R641 

R1041 

R647 

R649 

R651 

R1047 

R1051 

R655 

R1855 

R1057 

R1059 

R3457 

R3459 

R659 

R1859 

-  1067  1867  3467  ZnS04 . Zinc  Sulphate  . 


R366 


R663 


R662 


SUGGESTIVE  EQUIPMENTS  FOR  STUDENTS’  DESKS,  GENERAL  LABORATORY  USE  AND 

MAY  BE  OBTAINED  ON  APPLICATION 


STOCK 


418 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  3760 


No.  31-140 


No.  31-126 


No.  3770 


No.  3777 


31-132 

3760 

31-140 

31-126 

3770 


3776 

3777 

3782 

3784 


3790 

3792 


BOTTLE,  SPECIFIC  GRAVITY  (PYKNOMETER),  not  adjusted,  with  perforated  stopper  ground 

into  neck.  Capacity  25  cc . 

BOTTLES,  SPECIFIC  GRAVITY  (PYKNOMETERS),  accurately  adjusted,  with  perforated  stop¬ 
pers  ground  into  necks.  <  a  b  c  d 

Capacity,  cc.  10  25  50  100 

Each  $0.60  0.67  0.92  1.10 

BOTTLE,  SPECIFIC  GRAVITY  (PYKNOMETER),  double  wall  with  vacuum,  accurately  adjusted. 

Capacity  25  cc . 

BOTTLE,  SPECIFIC  GRAVITY  (PYKNOMETER)  with  GROUND-IN  CENTIGRADE  THER¬ 
MOMETER,  accurately  adjusted.  With  stoppered  capillary  tube.  Capacity  50  cc . 

BOTTLES,  SPECIMEN,  Bent  neck,  square,  —  will  lie  flat. 

a  b  c 

Small  Medium  Large 

Size,  ounces  )4  1  2 

Per  Dozen  $0.94  1.10  1.22 

BOTTLES,  WASHING,  DRECHSEL’S,  with  tubes  ground  into  the  neck. 


a  b  c 

Capacity,  cc.  125  250  500 

Each  $1.00  1.26  1.60 

BOTTLES,  WASHING,  with  antimony  rubber  stoppers  and  two  bent  tubes  as  illustrated. 

a  b  c 

Capacity,  cc.  250  500  1000 

Each  $0.32  .42  .68 

BOTTLES,  WEIGHING,  cylindrical,  light  blown  glass,  with  shoulder  and  ground-in  glass  stopper. 

a  b 


Capacity,  cc. 

20 

50 

Each 

$0.40 

.60 

:tles,  weighing, 

flat  bottom,  ground  glass 
a 

stopper 

Diameter,  mm. 

25 

40 

Length,  mm. 

50 

50 

Each 

$0.46 

.66 

No.  3792  No.  3790 

BREEDING  CAGE,  HARCOURT,  FOR  INSECTS.  Wooden  frame,  solid  bottom,  gauze  front, 
back,  top  and  sides.  One  end  hinged  and  provided  with  clasp.  Outside  dimensions  24  X  18  X  12 

inches . . 

BREEDING  CAGE,  KNOTT’S,  FOR  AQUATIC  INSECTS.  Can  also  be  used  for  wood  boring 
larvae,  etc.  This  outfit  is  in  reality  a  combination  aquarium  and  breeding  cage.  The  lower  part 
is  a  substantially  constructed  aquarium  13)4  X  8)4  X  8  inches  deep,  inside  dimensions.  With 
glass  front,  back  and  ends,  and  provided  with  stopcock.  The  upper  part  measures  14  X  11  X  9 
inches  over  all  and  is  provided  with  glass  front  and  gauze  back  and  ends.  One  end  is  hinged 
and  provided  with  clasp.  Substantially  framed  in  metal  and  painted  throughout.  Top  remova¬ 
ble.  Dimensions  over  all  14 %  inches  long,  10  inches  wide,  20)4  inches  high . 


$0.30 


2.16 

2.76 


$4.70 


13.76 


No.  3820  No.  3845 


No.  3860  No.  3861  No.  3865 


No.  3824 


No.  3825 


3800 

3802 

3803 
3806 
16-260 
3808 

3810 

3811 
3813 
3820 
3822 

3824 

3825 
3830 
3840 


3842 

3843 
3845 
3850 


3852 

3853 

3855 

3856 

3860 

3861 
3865 

3870 

3871 


BRUSH,  ACID,  of  spun  glass . $0.45 

BRUSH,  BEAKER  or  FUNNEL,  with  long  wooden  handle .  .22 

BRUSH,  BOTTLE,  with  wood  handle . . .  .20 

BRUSH,  BURETTE,  or  TUBE,  with  3-foot  wire  handle .  .10 

BRUSH,  CAMEL’S-HAIR,  J ^  inch  wide,  best  quality .  .16 

BRUSH,  “COUNTER,”  best  quality.  Should  be  in  every  laboratory .  .60 

BRUSH,  TEST  TUBE,  bristle  end,  wire  handle . , .  .07 

BRUSH,  TEST  TUBE,  sponge  end,  wire  handle .  .07 

BRUSH,  TUBE,  for  narrow  tubes,  wire  handle . •. . 03 

BULB,  CONNECTING,  Hopkins’  New  Form  . . ,  .  .  .  .36 

BULB,  POTASH,  Liebig’s,  with  five  bulbs . . . . .  .44 

BULB,  POTASH,  Mohr’s,  improved  by  Geissler .  1.25 

BULB,  POTASH,  Mohr’s,  improved  by  Geissler,  with  drying  tube  attached  .  1.60 

BULB  EXPANDER,  for  stretching  necks  of  rubber  bulbs  .  .50 

BURETTES,  MOHR’S,  for  pinchcock.  Without  fittings.  Subdivided  into  tenths. 

abed 
Capacity,  cc.  10  25  50  100 

Each  $0.46  .66  1.00  1.80 

BURETTE,  SCHELLBACH’S,  Mohr’s,  white  back  with  color  line,  without  fittings.  25  cc.  X  M  cc.  $1.26 

- ,  50  cc.  X  H  cc . .  1.48 

ATTACHMENT,  Glass  Tips,  Rubber  Tubing  and  Pinchcock  for  use  with  Nos.  3840, 3842  and  3843  above  .25 
BURETTES,  GEISSLER’S,  with  straight  glass  stopcocks.  Subdivided  into  tenths. 

abed 
Capacity,  cc.  10  25  50  100 

Each  $1.40  1.65  1.90  2.70 

BURETTE,  FRESENIUS’,  25  cc.  X  %  cc . , . $1.60 

- ,  50  cc.  X  %  cc .  2.20 

BURETTE,  SCHELLBACH’S,  Geissler’s,  white  back  with  color  line.  25  cc.  X  ;h6  cc .  1.60 

- ,  50  cc.  X  %  cc .  2.20 

BURETTE  CAPS . .  Per  Dozen  .60 

BURETTE  FLOAT,  Erdmann’s.  When  ordering,  state  the  accurate  inside  diameter  of  the  burette  .33 

BURETTE  FUNNELS . Each  .16 

BURETTE,  AUTOMATIC  ZERO,  three-way  stopcock  for  filling,  discharging  reservoir.  25  cc.  X  %  cc.  6.26 
- ,  50  cc.  X  H  cc .  6.00 


420 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  3875 


No.  3880 


No.  3881 


No.  3882  No.  3900  No.  3902 


No.  3883  No.  3886 


No.  3903  No.  3904  No.  3905 


No.  3906  No.  3907 


No.  3890 


3876  BURNER,  HIGH  TEMPERATURE  for  either  coal,  natural  or  gasoline  gas.  Both  air  and  gas  can  be 

regulated  separately.  The  special  feature  of  this  burner  is  that  the  whole  flame  is  practically  uniform 
in  temperature,  eliminating  entirely  the  cold  air  zone.  Height  6%  inches  with  1-inch  grid  ....  $1.85 


3880  BURNER,  TWO  TUBE,  with  air  regulators.  Height  6  inches,  diameter  of  tubes  %  inch .  1.30 

3881  BURNER,  THREE  TUBE  CLUSTER,  with  air  regulators.  Height  6  inches,  diameter  of  tubes  % 

inch .  1.60 

3882  BURNER,  FOUR  TUBE  CLUSTER,  with  air  regulators.  Height  6  inches,  diameter  of  tubes  J4  inch  1.95 

3883  BURNER,  FOUR  TUBE  GANG,  with  air  regulators  and  stopcocks.  Diameter  of  tubes  J4,  inch, 

height  8  inches .  4.46 


3885  BURNER,  BUNSEN’S,  FOUR  TUBE  GANG  with  support  and  trough  for  heating  tubes.  With  air 

regulators,  stopcocks  and  wing  tops.  Complete  as  illustrated . > .  9.25 

3890  BURNERS,  RING,  for  heating  funnels,  etc.  May  be  attached  to  any  support. 

a  b  c 

Diameter,  inches  3  4  6 

Each  $1.30  1.50  1.90 

BURNERS,  GLASS  BLOWERS’.  See  BLOWPIPES,  Page  416. 

BURNERS  FOR  SOLDERING  IRONS.  See  SOLDERING  IRON  HEATERS,  Page  479. 

For  other  BURNERS,  see  Pages  200-202. 


BURNER  ATTACHMENTS 

for 

Burners  with  Tubes  Jje-Inch  Diameter 

3900  BURNER  TUBE  for  blowpiping  with  yellow  flame.  Fits  inside  the  burner 

3901  BURNER  TIP  with  rest  for  blowpipe . 

3902  BURNER  CROWN  for  heating  small  dishes.  Gives  a  round  flame  .... 

3903  BURNER  GAUZE  TOP  giving  a  large  round  flame . 

3904  BURNER  WING  TOP  for  bending  glass  tubing,  etc . 

3905  BURNER  STAR . 

3906  BURNER  TRIPOD . ' . 

3907  BURNER  CHIMNEY  of  sheet  iron,  2  inches  diameter  at  the  bottom  .  .  . 


$0.13 

.12 


.38 

.24 

.09 


.21 


.17 

.14 


3915 

70-50A 

70- 50B 

71- 272 


3925 

3927 

3929 


3931 

3934 

3938 


CHEMISTRY  AND  BIOLOGY 


421 


CAGES,  BREEDING.  See  Page  418. 

CALCIUM  CHLORIDE  TUBES.  See  TUBES,  Page  490. 

CALCIUM  CHLORIDE  HOLDER  for  balance  cases . $0.33 

CANDLES,  PARAFFINE,  Sixes  (six  to  the  pound) .  Per  Dozen  .33 

CANDLES,  PARAFFINE,  Twelves  (twelve  to  the  pound) .  Per  Dozen  .20 

CANDLE,  STANDARD,  made  of  sperm,  six  to  the  pound.  Will  burn  120  grains 

(7.776  grams)  per  hour . Each  .25 


No.  3915 


CAPSULES,  CIRCULAR,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for 
characteristics.)  Plain,  glazed. 

a  b  c  d  e  f 


Diameter,  mm. 

35 

44 

51 

57  60 

70 

Depth  in  Center,  mm. 

13 

13 

13 

13  13 

16 

Price,  each 

$0.60 

.60 

.90 

.90  1.00 

1.26 

CAPSULES,  IGNITION,  ALUNDUM. 

(See  index, 

“Alundum  Ware,”  for  characteristics.) 

a 

b 

c 

d 

Diameter,  inches 

1VS2 

1  % 

1 5A 

Height,  inches 

K 

5A 

5A 

7A 

Capacity,  cc. 

7 

10 

18 

25 

Each 

$0.28 

.33 

.38 

.44 

CAPSULES,  RECTANGULAR, 

FUSED 

SILICA. 

(See  index, 

“Fused  Silica  Ware,”„for 

charac- 

teristics.)  Glazed. 

a 

b 

c 

Length,  mm. 

56 

48 

63 

Width,  mm. 

24 

38 

35 

Depth,  mm. 

10 

16 

10 

Each 

$1.00 

1.00 

1.25 

CARDS,  LOGARITHM.  See  LOGARITHM  CARDS,  Page  462. 


CASSEROLES,  AGATE  WARE,  with  attached  handle. 


~ - 7 

- - — -  .  - - f  - 

a 

b 

c 

d 

Capacity,  cc. 

250 

500 

750 

1000 

Each 

$0.20 

.22 

.28 

.30 

CASSEROLES, 

PORCELAIN,  with  porcelain  handle. 

a 

b 

c 

d 

e 

Capacity,  cc. 

125 

190 

375 

625 

1000 

Each 

$0.60 

.60 

1.00 

1.76 

2.00 

CASSEROLES, 

FUSED  SILICA.  (See  index, 

“Fused  Silica  Ware, 

”  for  characteristics.) 

a 

b 

c 

d 

e 

Diameter,  mm.  51 

70 

82 

95 

108 

Depth,  mm. 

25 

35 

44 

51 

63 

Each 

$1.76 

2.15 

2.65 

3.40 

4.40 

422 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


CENTRIFUGES 


No.  3945 


No.  3950 


No.  3955 


3946  CENTRIFUGE,  DOUBLE  ARM,  HAND  DRIVE,  accurately  cut  phosphor-bronze  gears  with  Babbitt 
metal  bearing  and  ball-bearing  rest.  Entirely  dust-proof.  Relief  clutch  in  handle  makes  it  impos¬ 
sible  to  stop  suddenly  and  disturb  sediment  in  the  glass  tubes.  New  style  holder  eliminates  danger 
of  breaking  the  tubes.  Speed,  2000  to  2500  R.  P.  M.,  obtained  with  ease  and  entire  safety. 

Complete  with  two  plain  and  two  graduated  15-cc.  glass  tubes . $13.60 

CENTRIFUGE,  ELECTRIC,  for  use  on  110  or  220  volts  D.  C.  and  A.  C.  Circuits,  on  direct  current 
approximately  1500  R.  P.  M.,  on  alternating  current,  approximately  1300  R.  P.  M.  Prices  include 
attachment  cord  and  plug,  with  rotating  head  with  metal  tubes.  Glass  parts  are  extra  as  listed. 

3948  - ,  for  110  volts,  D.  C.  With  Rheostat . 24.76 

3950  - — — ,  for  110  volts,  A.  C.  Without  Rheostat  (not  required) . . 22.26 

3952A  PLAIN  GLASS  TUBES,  15  cc.  for  above  centrifuges . Each  .12 

3952B  GRADUATED  GLASS  TUBES,  15  cc.  for  above  centrifuges . Each  .45 

3952C  RUBBER  CAPS  for  above  tubes . Each  .08 

3955  CENTRIFUGE,  ELECTRIC,  DOUBLE  ARM,  for  blood,  sputum,  and  milk  analysis.  Enclosed  rheostat 

for  control  of  speed.  Can  be  used  on  both  direct  and  alternating  current  at  110  volts,  but  not  ad¬ 
vised  or  guaranteed  on  direct  current  for  a  longer  period  than  three  to  five  minutes.  Improved  tube 
holder  eliminates  danger  of  breaking  the  tubes. 

Complete  with  two  plain  and  two  graduated  15-cc.  tubes  and  six  feet  of  electric  cord  with  plug  .  .  .  34.00 

Note: — When  either  direct  or  alternating  current  is  available,  it  is  advisable  to  order  this  Cen¬ 
trifuge  for  the  particular  current  on  which  the  motor  is  to  be  run. 


CENTRIFUGE  ACCESSORIES 


3957  PLAIN  GLASS  TUBE,  15  cc . $0.12 

3958  GRADUATED  GLASS  TUBE,  15  cc . . 45 

3969  HAEMATOKRIT,  with  tubes  for  examination  of  blood  and  sputum .  4.90 

3970  CHARCOAL  BLOCKS  for  blowpipe  work . . Per  Dozen  .46 

3975  CHART,  ATOMIC  WEIGHT,  compiled  by  Dr.  F.  W.  Clarke  and  reported  to  the  American  Chemical 

Society.  Corrected  to  1911.  Length  62  inches;  mounted  on  common  rollers .  1.35 

3976  CHART,  PERIODIC  LAW,  according  to  MendelejeS,  on  basis  of  0  =  16.  Revised  and  corrected  by 

Dr.  F.  W.  Clarke,  up  to  1911.  American  nomenclature.  Length  62  inches;  mounted  on  common 

rollers .  1.50 

77-80  CHART,  SPECTRUM,  after  Kirchhoff  and  Bunsen,  showing  beautifully  the  spectrum  of  the  sun,  K, 

Rb,  Cs,  Tl,  Na,  Li,  Ca,  Sr  and  Ba.  Mounted  on  linen  back  with  common  rollers .  4.25 

77-82  CHART,  SPECTRUM,  after  Kirchhoff  and  Bunsen,  showing  the  following  spectra,  —  In,  C,  Bo,  Mn, 

Pb,  Cu,  Co,  Ni  and  Fe.  Mounted  on  linen  back  with  common  rollers .  4.26 

6895  CHLORINE  TUBE,  after  Newell’s  “Descriptive  Chemistry,”  Experiment  23,  and  “General  Chemis¬ 
try,”  Experiment  29 .  .77 


CHEMISTRY  AND  BIOLOGY 


423 


No.  4000 


No.  4002 


No.  4004 


No.  4006 


No.  4008 


No.  4026  No.  4030 


No.  4040 


4000 

4002 

4004 

4006 

4008 

4011 

4013 

4015 


4017 

4020 


4022 


4026 

4026 

4030 


4032 


4034 

4036 


4040 

4042 

6305 


CLAMP,  BURETTE,  with  attached  Clamp  Holder.  Check  nut  to  adjust  to  any  position,  cork-lined 

jaws  open  to  1J4  inches . 

CLAMP,  DOUBLE  BURETTE,  closes  automatically  by  means  of  coiled  springs;  cork-lined  jaws  .  . 

CLAMP,  DOUBLE  BURETTE,  HOFFMAN’S,  opening  134  inches,  length  7  inches . 

CLAMP,  BUNSEN’S,  for  attaching  to  support  rods  of  ring  stands  by  means  of  Clamp  Holder.  Cork- 

lined  round  jaws  open  to  134  inches.  Without  Clamp  Holder . 

CLAMP,  BUNSEN’S,  for  attaching  to  support  rods  of  ring  stands  by  means  of  Clamp  Holder.  One 

flat  and  one  V-shaped  cork-lined  jaw.  Opens  to  2  inches.  W’ithout  Clamp  Holder . 

CLAMP  HOLDER  for  use  with  either  of  above  clamps . 

CLAMP,  BUNSEN’S  QUICK  ACTING,  compound  lever  adjustment.  Jaws  open  to  134  inches. 

Adjustment  to  full  opening  of  the  jaws  by  one-half  turn  of  the  turn  buckle . 

CLAMP,  BUNSEN’S  CONDENSER,  for  attaching  to  support  rod  of  ring  stands  by  means  of  Clamp 
Holder.  With  swivel  cork-lined  jaws  which  adapt  themselves  to  regular  or  irregular  shapes.  Jaws 

open  to  234  inches.  Without  Clamp  Holder . 

CLAMP  HOLDER  for  use  with  either  of  above  clamps . 

CLAMPS,  CABINET  MAKERS’,  of  malleable  iron,  japanned,  with  ball  and  socket,  swivel  cap  and 
screw..  a  b  c 

Open,  inches  3  4  6 

Each  $0.28  *  .38  .60 

CLAMPS,  HAND  SCREW,  of  wood,  superior  quality. 

a  b  c 

Length  of  Jaws,  inches  7  8  10 

Open,  inches  3  434  534 

Each  $0.40  .48  .60 


CLAMP,  “CUT-OFF,”  of  brass,  nickel-plated,  for  tubes  up  to  34-inch  diameter . 

CLAMP,  “CUT-OFF,”  nickel-plated,  with  34-inch  opening . 

CLAMPS  or  SCREW  COMPRESSORS,  of  brass,  nickel-plated.  Can  be  placed  upon  tube  without 
disconnecting  the  apparatus.  a  b 

Size,  inches  3 4  X  ^  34  X  134 

Each  $0.26  .30 


CLAMPS,  HOFFMAN’S  SCREW  COMPRESSORS,  nickel-plated. 

a  b 

Size,  inches  34  X  34  34  X  1 

Each  $0.25  .30 

CLAMP,  LEVER  SCREW  COMPRESSOR,  for  heavy  walled  tubing,  of  brass,  nickel-plated,  nicely 

finished  with  rounded  edges.  Size,  34  inch . 

CLAMPS,  MOHR’S  PINCHCOCKS,  of  brass,  nickel-plated. 

a  b  c 

Small  Medium  Large 

Length,  inches  234  234  3J4 

Each  $0.10  .12  .16 

CLAMP,  TEST  TUBE,  of  spring  wire.  Will  hold  test  tubes  from  34  to  134  inches  diameter.  Will 


not  burn . 

CLAMP,  TEST  TUBE,  of  wood,  with  wire  spring . 

CLAY  PIPES . Per  Dozen 


$0.33 

.80 

.95 

.30 

.38 

.16 

1.25 


.80 

.16 


.03 

.05 


.30 


.08 

.08 

.16 


424 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  J 


HARCOURT  CLINOSTATS 

STUDENTS’  —  ADVANCED 


No.  4050 

Showing  Pot  mounted  vertically 


No.  4050 

Showing  Pot  mounted  horizontally 


4060  HARCOURT  STUDENTS’  CLINOSTAT  for  small  pots  or  especially  for  seeds  growing  in  moss.  Con¬ 
sists  of  a  24-hour  clock  enclosed  in  a  practically  dust  and  moisture-proof  case  of  cast  metal.  De¬ 
signed  so  that  shaft  may  be  used  horizontally  or  vertically . $7.60 


No.  4052 

Showing  Pot  mounted  horizontally 


No.  4052 

Showing  Pot  mounted  vertically 


4062  HARCOURT  ADVANCED  CLINOSTAT  for  pots  up  to  3  inches  horizontally  or  larger  vertically  or  for 
seeds  growing  in  moss.  This  clinostat  consists  essentially  of  an  eight-day  clock  enclosed  in  a  prac¬ 
tically  dust  and  moisture-proof  casing  of  cast  metal.  A  3-inch  pot  is  recommended,  as  the  instrument 
works  best  with.this  size.  A  4-inch  pot  may  be  used,  however,  especially  in  the  vertical  position. 

Complete  with  set  of  clamps  for  holding  pot  as  illustrated . . $16.00 


CHEMISTRY  AND  BIOLOGY 


425 


4066 


COMBUSTION  BOATS,  ALUNDUM.  (See  index,  “Alundum  Ware,”  for  characteristics.) 

Valuable  for  all  kinds  of  determinations  involving  combustions  at  high  temperatures,  particularly  well 
suited  for  conditions  met  in  the  determination  of  carbon  in  iron  and  steel.  Wall,  V,  inch. 

a  b  c  d  e 


4067 


4069 


4071 


Length,  inches 

3H 

3% 

4H 

5 

5V 

Width,  inches 

k 

Vs 

Vs 

V 

y2 

Height,  inches 

% 

Vs 

K 

Ji 

Each 

$0.33 

.38 

.46 

.45 

.46 

COMBUSTION  BOAT  SHIELDS,  ALUNDUM.  (See  index,  “Alundum  Ware,”  for  characteristics.) 
For  protecting  combustion  boats  from  the  spattering  of  overheated  metal.  Wall,  %2  inch. 

a  b 


Length,  inches 

4>i 

5V2 

Bore,  inches 

13/i6 

Each 

$0.83 

1.10 

COMBUSTION  BOATS,  PLATINUM.  See  PLATINUM  WARE,  page  473. 


COMBUSTION  BOATS,  ROYAL  WORCESTER 
Porcelain  Ware,”  for  characteristics.)  a 


Length,  mm.  60 

Width,  mm.  10 

Each  $0.22 

COMBUSTION  BOATS,  FUSED  SILICA.  (See  index, 

a  b 


PORCELAIN, 
b 
75 
11 
.30 


(See 

c 

75 

15 

.35 


index,  “Royal 
d 

100 
18 

.66 


Worcester 


“Fused  Silica  Ware,”  for  characteristics.) 


Length,  mm. 

44 

76 

76 

102 

152 

Width,  mm. 

13 

13 

16 

16 

12 

Depth,  mm. 

8 

8 

10 

10 

12 

Each 

$0.60 

.76 

.90 

1.15 

1.60 

4076 


COMBUSTION  FURNACES.  See  FURNACES,  pages  440  to 
443. 

CONDENSERS,  LIEBIG’S,  GLASS,  with  rubber  connections 
and  adapters.  a  b  c 

Length,  inches  12  15  18 

Each  $0.96  1.26  1.40 


No.  4079 


'S' 

No.  4081 

4077  CONDENSER,  LIEBIG’S,  METAL,  for.  the  distillation  of  liquids,  made  entirely  of  brass,  highly 

polished.  Length  30  inches;  diameter  1J4  inches.  This  form  prevents  breakage . $2.76 

4079  CONDENSER,  SOXHLET’S  BALL,  copper,  tinned  inside,  for  use  with  extraction  apparatus.  Pol¬ 
ished  and  nickel-plated.  Diameter  4  inches .  3.00 

4081  CONDENSER,  SOXHLET’S  DOUBLE,  same  as  above,  but  with  two  bulbs,  4  inches  in  diameter. 

Connected  as  illustrated . . .  8.26 

4085  CONDENSERS,  ZINC,  with  pure  block  tin  worm. 

a  b  c  d  e 

Capacity,  gallons  1  2  3  5 

Each  $6.60  6.60  8.00  11.00  16.00 

90-310  CONNECTORS,  DOUBLE . Each  .11 

90-316  CONNECTORS,  TRIPLE . Each  .18 


I 


426  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6005 


CORKS,  REGULAR  LENGTH, 

Nos. 

TAPERED, 

0 

excellent  quality. 

1  2 

3 

4 

5 

Length,  inches 

% 

34 

34 

34 

34 

34 

Diameter  large  end,  inches 

34 

% 

34 

%0 

34 

134e 

Per  Dozen 

$0.03 

.03 

.03 

.03 

.04 

.04 

Per  Gross 

$0.15 

.16 

.17 

.20 

.23 

.30 

Nos. 

6 

7 

8 

9 

10 

11 

Length,  inches 

34 

X 

% 

X 

1 

1 

Diameter  large  end,  inches 

% 

x%8 

34 

15/l6 

1 

134 

Per  Dozen 

$0.06 

.06 

.07 

.08 

.09 

.10 

Per  Gross 

$0.33 

.44 

.55 

.65 

.80 

.90 

Nos. 

12 

13 

14 

15 

16 

17 

Length,  inches 

1 

1 

1 

1 

1 

1 

Diameter  large  end,  inches 

134 

1% 

134 

1*6 

134 

1*6 

Per  Dozen 

$0.12 

.12 

.14 

.16 

.18 

.20 

Per  Gross 

$1.00 

1.05 

1.20 

1.35 

1.70 

1.85 

Nos. 

18 

19 

20 

22 

24 

26 

Length,  inches 

1 

1 

1 

1 

1 

1 

Diameter,  large  end,  inches 

134 

1%6 

134 

IX 

134 

2 

Per  Dozen 

$0.22 

.26 

.30 

.35 

.42 

.54 

Per  Gross 

$1.95 

2.10 

2.20 

2.90 

3.40 

3.90 

CORKS,  SPECIE,  FLAT  or  JAR,  excellent  quality,  34  inch  thick. 

abed 

e 

f 

g 

h 

Diameter,  large  end,  inches 

1 

13 i 

134  m 

2 

234 

234 

2H 

Per  Dozen 

$0.08 

.11 

.16  .20 

.25 

.32 

.42 

.55 

4099  CORKS,  ASSORTED,  Nos.  0  to  11 . Per  Gross  $0.40 

CORKS,  RUBBER.  See  Rubber  Stoppers,  Page  478. 

6001  CORK  BORERS,  of  hard  metal  with  sharp  cutting  edge;  polished,  in  sets  with  punch. 

abed 
No.  in  Set  3  6  9  12 

Per  Set  $0.56  .90  1.50  2.00 

6003  CORK  BORERS,  of  hard  drawn  metal  with  sharp  cutting  edge,  each  borer  with  handle. 

abed 
No.  in  Set  3  6  9  12 

Per  Set  $0.98  2.16  2.65  3.76 


5005  CORK  BORER  SHARPENER,  a  steel  blade,  and  cone  of  brass,  wood  handle .  1.25 

5007  CORK  KNIFE,  good  steel  blade,  wood  handle .  .18 

5010  CORK  MATS  for  supporting  beakers,  flasks,  etc. 

a  b 

Diameter,  inches  4  6 


Each  $0.09  .14 


5013  CORK  PRESS,  Lever  Form,  japanned . 25 

5014  CORK  PRESS,  ROTARY,  wheel  form,  taking  corks  up  to  %-inch  diameter,  japanned .  .60 

5015  CORK  PRESS,  ROTARY,  wheel  form,  taking  corks  up  to  134  inches  diameter,  japanned .  .86 

5017  CORK  SCREW,  excellent  quality,  wood  handle  . .  .18 

5020  CORK  SHEET  for  lining  insect  boxes  and  cabinets,  10  X  30  mm.  X  5  mm.  thick .  .14 

COVER  GLASSES.  See  page  461. 


CHEMISTRY  AND  BIOLOGY 


427 


5030 


6031 

5031A 

5033 


CRUCIBLES,  ALUNDUM.  (See  index,  “Alundum  Ware,”  for  characteristics.)  For  general  labo¬ 
ratory  use  where  an  ignition  of  carbonaceous  material  is  involved.  Without  covers. 


abcdefghi 


Diameter  at  Top,  inches 

1* 

1  TS 

IK 

IK 

m 

IK 

IK 

2K 

2K 

Height,  inches 

1  Tf 

IK 

1  TS 

IK 

IK 

IK 

IK 

IK 

3 

Capacity,  cc. 

10 

15 

20 

25 

30 

40 

70 

80 

95 

Each 

$0.28 

.33 

.34 

.40 

.41 

.42 

.43 

.44 

.85 

CRUCIBLE  COVER,  ALUNDUM,  diameter  1  K  inches . 

- ,  diameter  1%  inches . . . 

CRUCIBLES,  GRAPHITE,  Dixon’s  genuine.  Capacities  given  are  actual  total,  not  working  capaci- 


ties,  which  are  variable. 

a 

b 

c 

d 

e 

Capacity,  ounces 

2 

4 

8 

12 

16 

Height,  inches 

2K 

2ii 

3K 

4  K 

5K 

Diameter,  inches 

ltt 

2K 

3K 

3K 

4K 

Each 

$0.52 

.52 

.92 

1.05 

1.12 

Nos.  6035  and  5039 


No.  6037 


$0.33 

.38 


5035 


6037 


5039 


5042 


6043 


CRUCIBLES,  SHEET  IRON,  with  Covers. 
Capacity,  cc. 

Each 


a  b  c  d 

20  ^IPW50  100  200 

$0.24  Iff*  .28  .33  .40 

CRUCIBLE,  SKIDMORE’S  IRON,  for  making  oxygen  from  MnO‘2,  calcination  of  chalk  with  recovery 
of  the  expelled  CO2,  manufacture  of  soda  from  cryolite,  preparation  of  ammonia,  destructive  dis¬ 
tillation  of  coal,  wood  or  other  organic  substance,  or  for  any  use  in  which  the  materials  employed 
or  evolved  do  not  act  destructively  on  hot  iron.  Can  be  used  equally  well  as  an  open  crucible, 

closed  crucible  or  retort.  Capacity  IK  ounces . $0.98 

CRUCIBLES,  SHEET  NICKEL,  with  covers. 

abed 


Capacity,  cc.  20 

30 

50 

100 

Each  $0.94 

1.10 

1.20 

1.95 

CRUCIBLES,  PLATINUM.  See  PLATINUM  WARE. 

CRUCIBLES,  PORCELAIN,  excellent  quality,  well  adapted  to  general  chemical  work  in  the  laboratory. 

a 

b 

c 

d 

e 

f 

g 

Capacity,  cc.  13 

14 

25 

45 

80 

140 

280 

Diameter  at  Top,  mm.  33 

41 

46 

55 

69 

82 

86 

Diameter  at  Bottom,  mm.  15 

17 

20 

21 

27 

32 

40 

Height,  mm.  25 

25 

30 

39 

45 

54 

72 

Each  $0.20 

.27 

.35 

.42 

.55 

.60 

.74 

CRUCIBLES,  PORCELAIN,  ROYAL  WORCESTER.  (See  index,  “Royal  Worcester  Porcelain  Ware,” 

for  characteristics.)  Glazed  inside  and  outside, 

with  covers  and  rings 

a 

b 

c 

d 

e 

f 

g  h 

Diameter  at  Top,  mm.  32 

37 

41 

46 

56 

67 

81  96 

Diameter  at  Bottom,  mm.  13 

15 

15 

18 

18 

23 

29  35 

Height,  mm.  19 

21 

25 

29 

36 

44 

52  65 

Capacity,  cc.  8 

12 

17 

30 

50 

90 

145  265 

Each  $0.20 

.22 

.30 

.38 

.62 

.57 

.66  .85 

428 


BOSTON 


6045 

6048 

6049 

6060 

6061 

6052 

5055 

6066A 

6055B 

6056 

5066A 

5066B 


L.  E.  KNOTT  APPARATUS 


C  O 


CRUCIBLES,  GOOCH,  PORCELAIN,  ROYAL  WORCESTER.  (See  Index,  “Royal  Worcester 
Porcelain  Ware,”  for  characteristics.)  Thin  wall,  bottom  unglazed,  outside  and  inside  glazed. 

a  be 


Diameter  at  Top,  mm. 

27 

35 

40 

Diameter  at  Bottom,  mm. 

18 

22 

25 

Height,  mm. 

30 

40 

43 

Capacity,  cc. 

10 

25 

35 

Each 

$0.34 

.48 

.58 

CRUCIBLES,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.)  Glazed.  Berlin 


porcelain  shape.  Measurements  given  are  outside  measurements. 


a 

b 

c 

d 

e 

f 

Height,  mm. 

19 

25 

28 

37 

44 

51 

Diameter  at  Top,  mm. 

41 

41 

48 

57 

67 

81 

Crucibles,  each 

$0.60 

.60 

.76 

.90 

1.25 

1.60 

Lids  to  Fit,  each 

$0.50 

.60 

.60 

.75 

.90 

1.10 

CRUCIBLES,  FUSED  SILICA. 

.  (See  index,  ‘ 

‘Fused  Silica  Ware”  for  characteristics.)  Unglazed. 

Measurements  are  outside 

measurements. 

a  b 

c 

d 

e 

f 

g 

h  i 

Height,  mm. 

111  102 

156 

190 

196 

213 

260 

324  508 

Diameter  at  Top,  mm. 

95  108 

114 

127 

149 

158 

196 

257  305 

Each 

$2.16  2.15 

3.16 

3.75 

4.00 

5.00 

8.00 

12.60  18.00 

CRUCIBLES,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.)  Glazed. 


Platinum  shape. 
Height,  mm. 

Diameter  at  Top,  mm. 
Crucibles,  each 
Lids  to  Fit,  each 


a 

51 

51 

$1.25 

$0.60 


b 

35 

35 

1.26 

.60 


c 

38 

43 

1.25 

.50 


CRUCIBLE,  FUSED  SILICA,  GOOCH,  %-inch  hole  in  bottom,  with¬ 
out  disc.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.) 
Outside  measurements,  —  height  inches  (41  mm.),  diameter  at 

top  1%  inches  (41  mm.)  Glazed . 

CRUCIBLE,  FUSED  SILICA,  SPECIAL.  (See  index,  “Fused  Silica 
Ware,”  for  characteristics.)  Glazed.  Outside  measurements,  — 
height  3^  inches  (81  mm.),  diameter  at  top  2%  inches  (73  mm.) 
CRUCIBLE,  FILTER,  ALUNDUM,  for  the  separation  of  liquids  from 
solids  in  laboratory  practice.  For  rapid  filtration,  it  is  necessary 
to  maintain  a  reduced  pressure  as  secured  by  an  aspirator,  etc. 
Special  glass  funnels  and  rubber  gaskets  are  necessary  to  give  the 
proper  fit  between  the  container  and  filtering  medium.  Three  de¬ 
grees  of  porosity  may  be  obtained,  —  36.9  per  cent.,  40.7  per  cent, 
and  47.4  per  cent.  We  carry  in  stock,  however,  40.7  per  cent.  only. 
Diameter  1%  inches,  height  inches,  capacity  25  cc. 


Proper  method  of  supporting 
Alundum  Crucible 


GLASS  SUPPORTING  FUNNEL  for  use  with  above  Crucible  and  Rubber  Gasket  following,  in  mak¬ 
ing  close  connection  with  the  filtering  medium . 

RUBBER  GASKET  for  use  with  above  Filter  Crucible  and  Supporting  Funnel  in  making  close  con¬ 
nection  with  the  filtering  medium  . 

CRUCIBLE,  FILTER,  ALUNDUM,  same  as  No.  6056,  but  1%  inches  diameter,  1^  inches  high  and 

35  cc.  capacity . 

GLASS  SUPPORTING  FUNNEL  for  use  with  above  Crucible  and  Rubber  Gasket  following,  in  mak¬ 
ing  close  connection  with  the  filtering  medium . 

RUBBER  GASKET  for  use  with  the  above  Filter  Crucible  and  Supporting  Funnel  in  making  a  close 
connection  with  the  filtering  medium . 


$0.36 


.42 


.08 


.42 

.48 

.08 


CHEMISTRY  AND  BIOLOGY 


429 


No.  5060 


6060 

5063 

* 


No.  5063  No.  5067  Nos.  5075  and  5076 

CRUCIBLE,  ROSE’S,  with  perforated  cover  and  delivery  tube,  unglazed,  vitreous. 

Capacity  30  cubic  centimeters  ... 1 . .  $0.60 

CRUCIBLES,  SAND,  round  form  with  lip. 

a  b  c  d  e 


Height,  inches 

2  % 

3 

3V2 

4 

4J^ 

Diameter,  inches 

1  Vz 

1% 

2H 

2Vs 

2Vs 

Per  Dozen 

$0.42 

.78 

.84 

.96 

1.44 

5066  CRUCIBLE  BLOCKS  for  No.  0  Porcelain  Crucibles,  according  to  specifications  by  Dr.  Lyman  C. 


Newell . Per  Dozen  .80 

6067  CRUCIBLE  FUNNEL,  of  glass,  according  to  Dr.  Lyman  C.  Newell .  .20 

6069  CRUCIBLE  RUBBER  TUBING  for  connecting  Gooch  Crucible  and  Funnel . Per  Foot  .30 

5076  CRUCIBLE  TONGS,  steel,  double  bend,  9-inch . 22 

6076  CRUCIBLE  TONGS,  steel,  nickel-plated,  double  bend,  9-inch . 33 

CULTURE  TUBES.  See  TUBES,  CULTURE,  Page  490. 


No.  31-260 


No.  6095 


No.  6098 


5080 


31-260 


6096 


6096 


6098 


CUPS,  POROUS. 

Diameter,  inches 
Height,  inches 
Each 


c 

2M 

5 

.26 


d 

3 

7 

.30 


Of 


a  b 

1H  2 

3  4 

$0.16  .20 

CYLINDERS  or  HYDROMETER  JARS  for  use  where  a  tall  jar  of  small  diameter  is  desired, 
clear  white  glass  with  foot  and  rim. 

a  b  c  d  e 

Size,  inches  12  Xl  12  X  2  15  X  2  15  X  3  18  X  3 

Each  $0.60  .56  .80  1.00  1.36 

CYLINDERS,  GRADUATED,  of  glass,  broad  base,  with  lip,  graduated  in  cubic  centimeters. 

a  b  c  d  e  f  g 

Capacity,  cc.  10  25  50  100  250  500  1000 

Each  $0.30  .36  .40  .62  .90  1.10  1.85 

CYLINDERS,  GRADUATED,  double  graduations,  reading  up  and  down,  of  glass,  broad  base,  with 
lip.  Graduated  in  cubic  centimeters. 

a  b  c  d  e  f 

Capacity,  cc.  25  50  100  250  500  1000 

Each  $0.38  .46  .66  .96  1.20  2.00 

CYLINDERS,  MIXING,  GRADUATED  AND  STOPPERED,  serviceable  when  making  standard  solu¬ 
tions.  Of  glass,  broad  base,  round  glass  stoppers,  graduated  in  cubic  centimeters. 

a  b  c  d  e  f  g 


Capacity,  cc. 
Each 


25 

$0.76 


50 

.85 


100 

.96 


200 

1.20 


250 

1.30 


500 

1.85 


1000 

2.25 


430 


L,  E.  KNOTT  APPARATUS  CO., 


BOSTON 


No.  5116  No.  6116  No.  6118 


DEFLAGRATING  SPOONS.  See  SPOONS,  DEFLAGRATING,  Page  479. 

5115  DESSICATOR  or  ACID  DISH,  PORCELAIN,  for  use  with  acid  in  dessicators . $0.85 

5116  DESSICATOR,  HARCOURT.  Consists  of  ground  glass  plate,  bell  glass  and  acid  dish  as  illustrated. 

Set .  2.46 


5118  DESSICATORS,  SCHEIBLER’S,  of  glass,  with  covers  ground  air-tight. 

a  b 

Diameter,  inches  4  6 

Each  $0.75  1.15 


5120  DESSICATOR  PLATES,  glazed,  on  three  small  feet,  for  use  in  Scheibler’s  Dessicators. 

a  b 


Diameter,  mm. 

95 

140 

No.  of  Holes 

3 

5 

Each 

$0.80 

1.10 

5122  DIAMOND  for  writing  on  glass.  Excellent  quality .  6.40 


No.  6126 


5125  DIGESTING  SHELF,  KJELDAHL’S,  oblong  form  of  sheet  iron,  with  rod  to  support  the  flasks.  The 
shelf  is  supported  on  adjustable  legs.  Size  24  inches  long,  5J6  inches  wide,  9J£  inches  high.  Com¬ 
plete  with  six  burners,  each  with  stopcock . $17.00 

6127  DIGESTING  SHELF,  ELECTRICALLY  HEATED,  KJELDAHL’S,  oblong  form  of  sheet  iron,  with 

rod  to  support  the  flasks.  Each  heater,  3J£  inches  in  diameter,  is  a  unit,  and  either  one  or  all  may 
be  used  at  one  time,  as  desired.  Size  24  inches  long,  inches  wide,  9  inches  high.  With  six  heaters  44.00 


5134  DISHES,  AGATE  WARE.  a 

Dimensions,  inches  X  1J6 

Capacity,  quarts 

Each  $0.16 


b 

x  i  y8 

i 

.18 


8MX 

2 

.22 


5136  DISHES,  CRYSTALLIZING. 


Of  clear  white  glass,  flat  bottoms,  straight  sides. 

a  b  c 

3  4 

.24  .32 


Diameter,  inches 
Each 


a 

2 

$0.18 


No.  5136 


I 


CHEMISTRY  AND  BIOLOGY 

EVAPORATING  DISHES 


5139 


5141 


6142 


DISHES,  EVAPORATING,  PURE  SHEET  NICKEL,  with  lip,  polished. 

„  k 

Diameter,  inches 

a 

2 

2% 

8lA 

Capacity,  cc. 

40 

100 

200 

Each 

$0.90 

1.30 

1.90 

DISHES,  EVAPORATING,  PORCELAIN,  excellent  quality,  well  adapted  to  general  chemical  work 

in  the  laboratory.  Thin,  uniform,  glazed  inside  and  outside. 

a  b 

c 

d 

e 

f  g 

h 

i 

j 

k 

1 

Size,  No.  00  0 

1 

2 

3 

4  5 

6 

7 

8 

9 

10 

Diameter,  cm.  7  8 

8A 

9 

10 

11  12 

14  H 

18 

21 H 

26^ 

31 

Capacity,  cc.  65  85 

110 

140 

165 

250  290 

475 

810 

1320 

2585 

4000 

Each  $0.16  .20 

.26 

.35 

.40 

.45  .55 

.70 

.90 

1.20 

1.76 

2.75 

DISHES,  EVAPORATING,  ROYAL  WORCESTER  PORCELAIN. 

(See  index,  “RoyalfrWorcester 

Porcelain  Ware,”  for  characteristics.)  Glazed  inside  and  outside, 

with  spout. 

a 

b 

c 

d 

e 

f 

g 

h 

1 

j 

Size  No.  00 

0 

1 

2 

3 

4 

5 

6 

7 

8 

Diameter,  outside,  mm.  70 

80 

85 

90 

100 

110 

120 

145 

185 

215 

Height,  mm.  27 

30 

33 

37 

42 

43 

50 

48 

54 

63 

Capacity,  cc.  60 

80 

100 

140 

175 

210 

300 

385 

765 

1285 

Each  $0.33 

.39 

.48 

.60 

.76 

.84 

.96 

1.35 

1.80 

2.16 

5145 


5146 


DISHES,  EVAPORATING,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.) 
Glazed.  Measurements  given  are  inside  measurements. 


a  b  c 


Diameter,  inches 

2 

2  H 

Depth,  inches 

13/ie 

1 

i % 

Diameter,  mm. 

51 

.  70 

82 

Depth,  mm. 

21 

25 

30 

Each 

$1.00 

1.16 

1.25 

ISHES,  EVAPORATING,  FUSED  SILICA. 

(See 

index, 

Unglazed. 

a  b 

c 

d 

e 

f 

Diameter,  inches 

5  H  SH 

6 

6 

7 

7 

Depth,  inches 

2M  2A 

2'A 

3 

2% 

3% 

Diameter,  mm. 

137  130 

152 

152 

178 

178 

Depth,  mm. 

57  63 

63 

76 

70 

95 

Each 

$2.86  3.00 

3.15 

3.60 

3.76 

3.90 

e 


3^ 

87A 

4J4 

Vs 

1 3A 

m 

89 

98 

108 

22 

30 

44 

1.35 

1.60 

1.85 

• 

‘Fused  Silica  Ware 

for  characteristics.) 

g 

h 

i 

j  k 

1  m 

n 

8 

8 

9 

9  12K 

15  H  18 

18 

3H 

4  H 

3V2 

4H  5K 

4  7 

8A 

20  3 

203 

229 

229  311 

394  458 

458 

82 

108 

89 

120  133 

102  178 

216 

4.35 

5.00 

6.00 

6.76  10.00 

12.00  14.00 

15.00 

432 


BOSTON 


« 

L.  E.  KNOTT  APPARATUS  CO., 


5148 


6150 


5151 


5154 


5155 

6157 


5159 

6161 


No.  5148 
DISHES,  FILTER,  ALUNDUM 

per  cent,  carried  in  stock, 
prices. 

Dimensions,  inches 
Capacity,  cc. 

Each 


No.  6160 

(See  index,  “Alundum  Ware,”  for  characteristics.)  Porosity  40.7 
Porosities  of  36.9  per  cent,  and  47.4  per  cent,  can  be  obtained  at  same 
a  b  c 

2^X1  4X2  5%  X  2 

50  300  400 

$0.44  1.10  1.66 


DISH,  INCINERATING,  ALUNDUM.  (See  index  “Alundum  Ware,”  for  characteristics.)  Rectangu¬ 
lar  form.  a  b  c  , 

Dimensions,  inches  4 %  X  4%  X  1  9 %  X  4  X  %  12%  X  6%  X  2% 

Each  $1.65  2.60  6.50 

- ,  round  form.  2%  inches  diameter,  %  inch  deep . 


$0.55 


No.  6169d 


No.  5165  No.  5167  No.  5159 

DISHES,  LEAD,  of  heavy  sheet  lead,  a  b  c 

Diameter,  inches  2  3  4 

Each  $0.12  .20  .32 

DISH,  LEAD,  rectangular,  for  etching . $0.20 

DISHES,  MILK,  ALUMINUM,  flat  bottom,  straight  sides.  a  b  c 

Diameter,  inches  2  3  4 

Each  $0.21  .33  .60 

DISHES,  PETRI  or  DOUBLE,  glass  cover,  diameter  10  centimeters .  .28 

DISHES,  PETRI  or  DOUBLE,  porous  porcelain  cover,  according  to  Boston  Board  of  Health.  Diam¬ 
eter  10  centimeters . . .  .30 


No.  6165 

5165  DISHES,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.)  Flat,  with  lip, 


glazed. 

a 

b 

c 

d 

Diameter,  mm. 

63 

73 

95 

124 

Depth,  mm. 

13 

13 

18 

21 

Each 

$1.16 

1.25 

1.35 

1.85 

6167  DISH,  STAINING,  with  cover,  for  staining  slide  sections . $0.75 

6169  DISHES,  STENDER  or  PREPARATION,  of  clear  white  glass,  covers  grooved  and  ground  on. 

abed 
m  2  2%  3% 

H  1  1  Vs  3% 

$0.12  .15  .22  .25 


Diameter,  inches 
Height,  inches 
Each 


CHEMISTRY  AND  BIOLOGY 


433 


DISSECTING  INSTRUMENTS 


No.  5196  No.  5190  No.  5182  No.  5184  No.  5186  No.  5188  No.  5192  No.  5194  No.  5201  No.  5208  No.  5210  No.  5214 


No.  5216 


No.  6230  No.  6232  No.  6234  No.  6224  No.  5226  No.  6227 


6180  BLOWPIPE,  2y  inches,  for  inflating  arteries,  etc . $0.16 

6181  DISSECTING  PAN,  BUSSEY’S,  iy2  X  11  inches,  with  black  wax . 48 

6182  FORCEPS,  steel,  6-inch,  nickel-plated,  straight,  heavy  corrugated  points,  corrugated  handles  .  .  .  .46 

6184  FORCEPS,  FINE,  STRAIGHT,  steel,  4-inch,  nickel-plated,  corrugated  points,  corrugated  handle, 

with  guide  pin .  .46 

6186  FORCEPS,  FINE,  CURVED,  steel,  4-inch,  nickel-plated,  corrugated  points,  corrugated  handle,  with 

guide  pins .  .60 

6188  FORCEPS,  FINE  POINTS,  plain,  4J^_inch,  smooth  handles .  .16 

6190  FORCEPS,  BONE-CUTTING,  6J^-inch,  strong,  accurately  made,  knife  shaped  blades.  With  lock  .  .  1.16 

6192  FORCEPS,  COVER-GLASS,  STEWART’S,  4^-inch,  nickel-plated  steel  wire . 16 

6194  FORCEPS,  COVER-GLASS,  NOVY’S,  WITH  LOCK,  4^-inch.  The  thin  edge  of  the  lower  blade 

enables  one  to  pick  up  a  cover  glass  readily.  The  curving  pointed  blade  prevents  capillary  drainage  1.26 

6196  HOOKS  AND  CHAINS,  triple  hooks  and  connecting  chains,  nickel-plated .  .18 

5198  NEEDLES,  STRAIGHT,  wood  handle  . Per  Dozen  .30 

6199  NEEDLES,  BENT,  wood  handle  . Per  Dozen  .30 

6201  NEEDLE  HOLDER,  bone  handle  with  clamping  holder  for  straight  or  bent  needles,  3  J^-inch . 10 

6203  NEEDLES,  STRAIGHT,  for  use  with  above  holder  . Per  Dozen  .10 

6204  NEEDLES,  BENT,  for  use  with  above  holder  . Per  Dozen  .10 

6208  RAZOR,  SECTION,  folding  handle,  superior  quality,  3-inch  blade,  one  side  flat,  straight  edge  .  .  .  1.10 

6210  RAZOR,  SECTION,  straight  handle,  finest  steel,  3-inch  blade,  one  side  flat,  straight  edge .  1.86 

5214  SAW,  BONE,  superior  grade,  4  inches  long .  1.76 

6216  SCALPEL,  1%-inch  blade,  excellent  quality  steel,  ebony  handles  riveted  to  the  blade .  .40 

6217  - - ,  1  y  inch  blade . 40 

6218  - ,  1-inch  blade .  .40 

6220  SCALPEL,  CARTILAGE  (Cartilage  Knife),  63^-inch,  all  steel;  blade  2  inches  long;  corrugated  handle  .  .66 

6224  SCISSORS,  4 y2  inch,  medium  heavy,  straight,  fine  cutting  points . 48 

5226  SCISSORS,  4H  inch,  fine  sharp  straight  points;  heavy  pattern . 66 

5227  SCISSORS,  4H-»nch,  fine  sharp  curved  points;  heavy  pattern . 66 

6230  SECTION  LIFTER,  thin  flexible  blade,  \%  X  %  inches,  ebony  handle  riveted  to  blade . 30 

6232  - ,  blade  1  %  X  %  inches .  .35 

6234  - ,  blade  2  X  1H  inches .  .40 

6238  TENACULUM,  steel  shank  with  sharp  hook,  ebony  handle  riveted  to  blade .  .36 

6240  TENACULUM  AND  NEEDLE,  solid  steel,  sharp  hook,  sharp  point . 40 


434 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  » 


DISSECTING  SETS 

Our  sets  of  dissecting  instruments  have  been  made  up  with  great  care.  The  instruments  are  of  finely  tempered 
steel  and  the  shapes  and  sizes  chosen  for  the  various  sets  have  met  with  complete  approval  of  teachers  of  the  natural 
sciences. 

The  cases  are  of  the  folding  pocket  form  with  separate  loops  for  each  instrument.  The  leatherette  cases  are 
strong  and  durable.  They  are  lined  with  cloth,  with  cloth  flaps.  The  leather  cases  are  made  of  black  morocco  and 
are  lined  with  leather  with  chamois  flaps  to  protect  the  instruments. 


No.  5256 


No.  6257 


No.  5269 


n 

nji 

II  gH 

PI 

* 

i  i 

1  |J 

No.  6261 


6265  HARCOURT  FIRST  YEAR  STUDENTS’  DISSECTING  SET,  one  fold  leatherette  case  containing 

Ruler  and  six  high-grade  instruments  as  follows:  —  2  Dissecting  Needles,  Forceps,  Scissors,  Scalpel 
and  Pipette . Set  $1.20 

6257  HARCOURT  ADVANCED  STUDENTS’  DISSECTING  SET,  one  fold  leatherette  case  containing 

five  high  grade  instruments,  —  2  Bone-handle  Clamping  Needle  Holders  with  needle  for  each,  For¬ 
ceps,  Scissors  and  Scalpel . Set  1.25 

6259  HARCOURT  SUPERIOR  DISSECTING  SET,  two  fold  leatherette  case  containing,  —  Cartilage 

Knife,  Scalpel,  Tenaculum,  Forceps,  Blowpipe,  Scissors  and  Hooks  and  Chains . Set  2.66 

6261  THE  UNIVERSITY  DISSECTING  SET,  —  morocco  leather  case,  leather  lined,  chamois  flaps,  con¬ 
taining  the  following  extra  fine  grade  instruments,  —  two  Bone-handle  Clamping  Needle  Holders, 
each  with  needle,  Fine-pointed  Curved  Forceps,  Fine-pointed  Scissors,  Medium  Scissors,  Blowpipe, 

Hooks  and  Chains,  Tenaculum,  Heavy  Forceps  and  three  sizes  of  Scalpels.  Twelve  instruments 
in  case . Set  3.00 


6263  HARCOURT  RESEARCH  DISSECTING  SET,  leatherette  covered  case  with  clasp,  containing 
the  following  extra  fine  grade  instruments,  —  Cartilage  Knife,  four  sizes  of  Scalpels,  Tenaculum, 
Forceps,  Hooks  and  Chains,  Blowpipe,  Scissors  and  Bone  Saw.  Eleven  instruments  in  case.  Set  6.76 


CHEMISTRY  AND  BIOLOGY 


435 


No.  5276  No.  5277  No.  5286  No.  5285A  No.  5285B 

6275  DISTILLING  APPARATUS,  HEAVY  POLISHED  COPPER,  for  destructive  distillation  of  heavy  oils 
and  other  liquids  or  solids  requiring  a  high  heat.  The  distillation  may  be  made  by  live  steam  or 
by  direct  heat  with  or  without  agitation  by  hot  air  blown  through,  as  desired.  Capacity  gallon  $18.50 
5277  DISTILLING  APPARATUS,  SALLERTON’S,  POLISHED  COPPER,  for  determining  percentage  of 


alcohol  in  wine,  beer,  cider,  etc.  Capacity  pint .  9.76 

5415  DISTILLATION  FLASKS,  FRACTIONAL,  with  side  tubes.  (For  illustration,  see  page  438) 

a  bed  — e  f 

Capacity,  cc.  15  30  100  250  500  1000 

Each  $0.20  .26  .45  .60  .75  .95 

5285  DISTILLATION  TUBE,  FRACTIONAL.  Plain,  with  side  tube . $0.26 

5285A  - ,  with  one  bulb .  .44 

5285B  - ,  with  two  bulbs .  .56 


DRYING  OVENS 


These  ovens  are  of  polished  copper,  with  tubulations  for  thermometer  and  gas  regulator.  Extra  sheet  iron  bot¬ 
tom,  single  and  double  wall,  as  listed  below. 


No.  6295 


No.  5299 


5295  DRYING  OVEN,  single  wall,  on  iron  stand  8  inches  high,  with  set  screw  by  which  oven  is  held  firmly. 

Inside  dimensions,  6X8X6  inches  deep.  With  one  removable  shelf . $5.50 

5297  DRYING  OVEN,  double  wall,  otherwise  same  as  above.  With  one  removable  shelf .  7.75 

6299  DRYING  OVEN,  double  wall,  same  as  No.  6297,  but  with  the  addition  of  water  bath  top.  With  one 

removable  shell . 9.76 

6301  DRYING  OVEN,  double  wall,  same  as  No.  5297,  but  inside  dimensions  8  X  10  X  8  inches  high.  With 

one  removable  shelf . 11.76 

DRYING  PAPER.  See  page  472. 


436  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


5310 

5312 

5314 

5316 

5325 


3830 

5330 

5332 

5335 

5342 


6344 


ELECTRIC  IRON  with  “Inverted  Rack,”  enabling  the  iron  to  be  used  as  a  stove  when  so  desired.  Size, 
334  X  7  inches,  weight  5  pounds.  Consumption  475  watts  on  120  volts  either  D.  C.  or  A.  C.  With 

6  feet  cord  and  lamp  socket  plug . 

ELECTRIC  STOVE,  PORTABLE,  4 J4  inches  diameter,  for  use  on  either  D.  C.  or  A.  C.  circuits  of  120 
volts.  Consumption  250  watts;  mounted  on  enamel  slate  base.  With  6  feet  cord  and  plug  for  at¬ 
taching  lamp  socket . 

ELECTRIC  SOLDERING  IRON,  14  ounce,  34  X  11  inches,  for  use  on  either  D.  C.  or  A.  C.  circuits 

of  120  volts.  Consumption  75  watts.  With  cord  and  plug . 

ELECTRIC  PORTABLE  WATER  HEATER,  of  copper,  nickel-plated.  Capacity  one  pint.  For  use 
on  either  D.  C.  or  A.  C.  circuits  of  110  volts.  Consumption  400  watts.  With  6  feet  of  cord  .  .  . 
ELECTROLYSIS  APPARATUS.  See  Index. 

EUDIOMETERS,  BUNSEN’S,  with  platinum  electrodes,  graduated  to  34  cc. 

a  b 

Capacity,  cc.  50  100 

Each  $2.70  3.40 

EVAPORATING  DISHES.  See  DISHES,  EVAPORATING. 

EXPANDER,  TUBE  AND  BULB,  for  stretching  necks  of  rubber  bulbs  and  tubes..  For  illustration 

see  Page  419 . 

EXTRACTION  APPARATUS,  SOXHLET’S.  Complete  with  flask,  extractor  and  condenser. 

a  b  c 

Small  Medium  Large 

Each  $2.76  3.00  3.76 

EXTRACTION  APPARATUS,  SOXHLET’S.  The  Water  Bath  is  made  of  heavy  polished  copper,  tinned 
inside.  23  inches  long,  4  inches  deep  and  434  inches  wide,  with  six  holes  234  inches  in  diameter, 

on  legs  7  inches  high.  Extreme  height,  including  rods,  is  31  inches.  Rack  adjustable . 

EXTRACTION  CARTRIDGES.  Seamless,  of  fat-free  paper.  May  be  used  repeatedly.  Per  package 
EXTRACTION  FLASKS.  See  FLASKS,  Page  438. 

EXTRACTION  THIMBLES,  ALUNDUM.  fSee  index,  “Alundum  Ware,”  for  characteristics.)  Alun- 
dum  thimbles,  are  preferable  to  paper  thimbles  in  that  they  remain  constant  in  weight  and  may  be 
used  an  indefinite  number  of  times  and  permit  the  ignition  of  the  extracted  residue  without  remov¬ 
ing  the  residue  from  the  thimble.  Thickness  of  wall,  about  one  mm. 

Three  degrees  of  porosity  may  be  obtained,  —  36.9  per  cent.  —  40.7  per  cent,  and  47.4  per  cent.  We 
carry  in  stock,  however,  only  40.7  per  cent. 

a  b  c  d  e  f  g 


Outside  diameter,  mm.  6 

19 

25 

30 

34 

35 

45 

Height,  mm. 

31 

90 

70 

80 

100 

55 

127 

Round  Bottom,  each 

$0.30 

.70 

1.16 

Flat  Bottom,  each 

.60 

00 

.60 

.60 

EXTRACTION  TUBES, 

SOXHLET’S. 

a 

b 

c 

Small 

Medium 

Large 

Each 

$1.76 

2.10 

2.40 

FAUCETS,  WATER.  See  Page  9. 


$3.90 

4.75 
6.80 

6.75 


.60 


24.25 

3.50 


}- 


CHEMISTRY  AND  BIOLOGY 


437 


5360 

6351 

6365 


FILE,  ROUND,  rat-tail,  good  quality,  5  inches  long . $0.16 


.15 


m 

234 

•  3  ' 

434 

i  X 

i  v% 

2 

334 

20 

/  50 

60 

100 

$0.33 

.39 

.45 

.56 

.08 

.12 

.16 


FILE,  TRIANGULAR,  glass  cutting,  good  quality,  5  inches  long . 

FILTER  CONES,  ALUNDUM,  for  use  with  the  ordinary  60  degree  funnel  to  which  it  is  held  firmly 
by  stretching  a  rubber  gasket  over  the  top  of  the  funnel  before  introducing  the  cone.  Light  alumi¬ 
num  stands  are  supplied,  without  extra  charge,  with  the  cones  for  supporting  them  on  the  balance  pan. 

Three  degrees  of  porosity  may  be  obtained,  —  36.9  per  cent.,  40.7  per  cent,  and  47.4  per  cent.  Our 
stock,  however,  contains  Filter  Cones  40.7  per  cent.  only. 

abed 

Diameter,  inches 
Height,  inches 
Capacity,  cc. 

Each 

5356A  RUBBER  GASKETS  for  use  with  above  Filter  Cones  in  making  the  proper  connections  with  the  fun¬ 
nels.  For  use  with  Nos.  6355  a  and  b . *.  .  . . 

5356B  - ,  for  use  with  No.  5355c . 

6366C  - ,  for  use  with  No.  5355d .  ...... 

FILTER  DISCS.  See  PLATES,  FILTER,  Page  472. 

We  carry  in  stock  two  lines  of  FILTER  PAPER, — ’the  HARCOURT  FILTER  PAPER  for  general  laboratory 
use  in  qualitative  work  and  the  WHATMAN  FILTER  PAPER  selected  with  extreme  care  for  different  kinds  of 
quantitative  work. 

5365  FILTER  PAPER,  HARCOURT,  round,  a  pure  white  paper  of  exceptional  quality,  of  tough  texture  and 
very  rapid.  This  grade  of  paper  is  suggested  for  general  use  in  the  laboratory  and  for  all  qualitative 
work.  a  b  c  d  e  f 

Diameter,  inches  3  4  5  6  -  8  10 

Per  Box  of  100  Papers  $0.09  -  .15  .18  .20  .30  .45 

6366  - ,  in  sheets,  same  quality  as  above.  Sheets  19  X  19  inches  ....  Per  Quire  $0.38;  Per  Ream  $6.60 

Few,  if  any,  manufacturers  have  devoted  so  much  attention  during  the  past  twenty  years  to  the  chemical  prob¬ 
lems  pertaining  to  the  manufacture  of  high  grade  papers  as  the  Whatman  Paper  Company.  We  are  now  able  to 
offer  their  high  grade  line  of  filter  papers  which  we  are  able  to  guarantee  to  be  of  the  very  highest  quality. 

Please  note  the  low  percentage  of  ash  in  the  various  sizes  given  below. 

6370  WHATMAN  NO.  1  FILTER  PAPER  for  general  quantitative  and  qualitative  work.  The  paper  is 


6371 

6372 


6373 

5374 


6376 


tasteless  and  free  from  chlorine  and  starch. 

a 

Diameter,  cm.  9 

Ash  per  Circle,  gram  .00076 

Price  per  100  $0.19 

- ,  in  sheets,  same  quality  as  above. 


6385 

5386 


Retains  barium  sulphate  when  properly  precipitated, 
bed 
11  1234  15 

.0017  .0016  .0021 

.22  .24  .34 

Sheets  18J4  X  22 inches  . . Per  C  $3.24 

WHATMAN  NO.  4  FILTER  PAPER  for  filtering  fruit  juices,  syrups,  oils,  varnishes,  etc. 

a  b  c  d  e 

Diameter,  cm.  11  1234  15  1834  32 

Price  per  100  $0.34  .36  .46  .58  1.44 

- ,  in  sheets,  same  quality  as  above.  Sheets  1834  X  2234  inches . Per  C  6.04 

WHATMAN  NO.  30  FILTER  PAPER  for  quantitative  work.  This  paper  has  low  ash  and  close  texture. 
Treated  by  hydrochloric  acid  to  remove  such  chemical  salts  as  are  normally  contained  in  the  fibre. 

abed 
Diameter,  cm.  9  11  1234  15 

Ash  per  Circle,  gram  .00056  .00089  .00108  .00159 

Price  per  100  $0.60  .75  .96  1.25 

WHATMAN  NO.  40  “ASHLESS”  FILTER  PAPER  for  quantitative  work  in  which  a  high  degree  of 
accuracy  is  desirable.  This  paper  being  pure,  gives  a  very  low  ash  and  being  close  in  texture,  will 
retain  even  the  finest  precipitates.  Subjected  to  a  combined  treatment  of  hydrochloric  and  hy¬ 
drofluoric  acid,  it  is  lower  in  ash  than  No.  30  above,  the  hydrochloric  acid  having  the  effect  of  remov¬ 
ing  traces  of  silicious  matter.  a  b  c  d 

Diameter,  cm.  9  11  1234  15 

Ash  per  Circle,  gram  .00016  .00024  .00030  .00043 

Price  per  100  $1.08  1.32  1.44  1.68 

FILTER  PLATES,  WITTE’S,  PORCELAIN.  Diameter  134  inches  .  .  .  .  ' . 36 

- ,  diameter  234  inches .  -40 


43« 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


1 


5405 

6407 

5408 

5409 

5411 

5413 

5415 


6423 

5425 

6427 

6429 

5430 


5431 

6433 


FLASKS,  FLAT  BOTTOM. 

a 

Capacity,  cc.  25 

Each  $0.07 

FLASKS,  FLAT  BOTTOM, 
a 

Capacity,  cc.  50 

Takes  Stopper  No.  Kll 
Each  $0.12 


b 

50 

.08 

“PYREX.” 
b  c 

100  150 

Kll  K13 

.13  .16 


c  d 

100  250 

.10  .14 

(See  index,  “I 


d 

200 

K15 

.18 


e 

300 

K21 

.21 


e 

500 

.20 
ex  Gli 
f 

400 
K21 
.26 

FLASKS,  RING  NECK,  FLAT  BOTTOM,  “PYSIEX  GLASS.” 

Capacity,  cc. 

Takes  Stopper  No. 

Each 

FLASKS,  FLAT  BOTTOM,  “FUSED  SILICA.”  (See  index, 
Spherical  shape.  a  b  c 

Capacity,  cc.  50  100  150 

Each  $2.75  4.00  4.25 

FLASKS,  ROUND  BOTTOM,  spherical.  a 

Capacity,  cc.  100 

Each  $0.10 

FLASKS,  ROUND  BOTTOM,  “FUSED  SILICA.”  (See  index, 
a  b  c  d  e  f 
Capacity,  cc.  50  100  150  200  250  500 

Each  $2.75  4.00  4.25  6.00  6.26  7.50 


f 

1000 

.30 


g 

2000 

.60 


h 

4000 

1.10 


g 

h 

i  j 

k  1 

500 

700 

1000  1500 

2000  3000 

K25 

K28  • 

K30  K30 

K33  K37 

.29 

.36 

.43  .61 

.60  .76 

a 

b 

c 

d 

500 

700 

1000 

2000 

K28 

K28 

K30 

K37 

$0.38 

.47 

.56 

.78 

“Fused 

Silica  Ware,”  for  characteristics.) 

d 

„  e 

f 

g 

200 

250 

500 

1000 

5.00 

6.25 

7.60 

16.00 

b 

c 

d 

250 

500 

1000 

.14 

.20 

.30 

“Fused  Silica  Ware,”  for  characteristics.) 
g 

1000 

16.00 

b  c  d  e  f 


Capacity,  cc. 

15  30 

100 

250  500 

1000 

Each 

$0.20  .26 

.46 

.60  .75 

.95 

6417 

FLASKS,  DISTILLATION, 

“FUSED  SILICA.” 

(See  index,  “Fused  Silica  Ware, 

for  characteristics.) 

Spherical,  with  side  arm. 

a 

b 

c  d 

e 

f  g 

Capacity,  cc. 

50 

100 

150  200 

250 

500  1000 

Each 

$3.25 

4.76 

5.00  6.00 

7.60 

9.00  18.50 

5419 

FLASKS,  ERLENMEYER. 

a 

b 

c 

d 

e 

Capacity,  cc. 

60 

125 

250 

500 

1000 

Each 

$0.10 

.12 

.14 

.18 

.30 

6421 

FLASKS,  ERLENMEYER,  “PYREX  GLASS.”  (See  index 

:,  “Pyrex  Glassware, 

for  characteristics.) 

a 

b 

c  d 

e 

f  g  h 

i 

j  k 

1 

Capacity,  cc.  50 

100 

150  200 

250 

300  500  600 

750 

1000  1500 

2000 

Takes  Stopper  No.  Kll 

K17 

K19  K23 

K23 

K25  K25  K25 

K30 

K33  K37 

K43 

Each  $0.11 

.12 

.13  .16 

.17 

.19  .27  .29 

.33 

.42  .51 

.60 

FLASK,  ERLENMEYER,  WIDE  MOUTH,  “PYREX  GLASS.” 

6%  inches,  diameter  of  mouth  2  inches;  takes  rubber  stopper  K47. 
FLASKS,  EXTRACTION,  SOXHLET’S,  large  mouth.  a 

Capacity,  cc.  60 

Each  $0.15 


Greatest  diameter  2%  inches,  height 

Capacity  500  cc . $0.27 

b  c  d  e 

100  250  500  1000 

.20  .30  .40  .60 


Height  3>y%  inches,  diameter 
Height  91JAe  inches,  diam- 


FLASK,  EXTRACTION,  “PYREX.”  Round  bottom,  capacity  100  cc. 

2 %  inches,  diameter  of  neck  1%2  inches . 

FLASK,  EXTRACTION,  “PYREX.”  Round  bottom,  capacity  2000  cc. 

eter  6jj6  inches,  diameter  of  neck  22%2  inches  . 

FLASKS,  FILTERING,  conical  form  with  side  neck,  heavy  glass,  uniform.  a  b 

Capacity,  cc.  250  500 

Each  $0.30  .45 

FLASK,  KJELDAHL  or  DIGESTION,  for  nitrogen  determinations.  Capacity  200  cubic  centimeters 
FLASKS,  KJELDAHL  or  DIGESTION,  “PYREX.”  (See  index,  “Pyrex  Glassware,”  for  charac¬ 
teristics.)  Round  bottom,  long  neck.  a  b  c 

Capacity,  cc.  300  500  800 

Each  $0.28  .37  .45 


$0.15 

.69 


$0.22 


439 


No.  5466 


No.  6468 


No.  5464 


6435  FLASKS,  VOLUMETRIC,  without  glass  stopper,  graduated  with  one  and  two  marks  as  follows: 


6437 


6-270 


6-272 

6446 

6460 


3865 

6467 


6459 

6460 


6462 

6464 

6466 

6468 

6470 

5470A 

6472 

6472A 


J 

200  &  220 

.65 

g 

1000 
1.35 


- ,  tapped  %  X 

SUPPORT  RODS. 


abode  f  g  h  i 

Capacity,  cc.  5  10  20  25  50  50  &  55  100  100  &  110  200 

Each  $0.15  .20  .26  .30  .36  .40  .46  .48  .60 

FLASKS,  VOLUMETRIC,  with  glass  stopper,  graduated  as  follows. 

a  b  c  d  e  f 

Capacity,  cc.  25  50  100  200  250  500 

Each  $0.60  .60  .70  .75  .80  .96 

FLUSH  PLATE,  nickel-plated,  for  inserting  in  any  table  flush  with  the  top  surface.  When  fitted 
to  a  table  and  screwed  into  place,  it  offers  an  excellent  socket  for  a  support  rod  for  funnel  and  filter 

rings,  clamps,  etc.  Tapped  )4  X  20  for  10  mm.  rods . $0.35 

16  for  13  mm.  rods . . .  .46 

See  page  10. 

FORCEPS,  STEEL,  5-inch,  for  handling  phosphorous,  potassium,  etc . 10 

FUNNELS,  BUNSEN’S,  stem  cut  at  an  angle  of  60°. 

a  b 

Diameter,  inches  2  2)4 

Each  $0.16  .18 

FUNNELS,  BURETTE  (For  illustration  see  Page  419) . Each  .16 

FUNNELS,  SEPARATORY,  cylindrical. 

Capacity,  cc. 

Each 

FUNNELS,  SEPARATORY,  globe  shape. 

Capacity,  cc. 

Each 

FUNNELS,  SEPARATORY,  SQUIBB’S,  pear  shape,  with  glass  stopper. 

a  b  c 

Capacity,  cc.  125  250  500 

Each  $2.35  3.40  4.30 

FUNNEL,  GRADUATED,  SEPARATORY,  CYLINDRICAL.  Long  stem,  capacity  250  cc . $4.26 

FUNNEL,  POLISHED  COPPER,  DOUBLE  WALL,  for  hot  filtrations .  4.86 

FUNNEL,  KOCH’S,  POLISHED  COPPER,  single  wall  for  hot  filtrations.  With  legs .  3.70 

- ,  double  wall  for  hot  filtrations.  With  legs .  6.76 

FUNNEL,  PORCELAIN,  small  perforations,  for  use  in  rapid  filtrations,  diameter  4)4  inches . 70 

- ,  diameter  5)4  inches . 90 

FUNNEL,  BUCHNER,  PORCELAIN,  with  fixed  perforated  porcelain  plate,  diameter  80  millimeters  .90 
- ,  diameter  100  millimeters . ■ .  1.30 


c  d 

e 

f 

g 

h 

3  4 

5 

6 

8 

10 

.20  .25 

.35 

.45 

.76 

1.60 

Page  419)  .  . 

a 

b 

c 

30 

60 

125 

$1.20 

1.46 

1.90 

a 

b 

c 

d 

e 

60 

125 

250 

500 

1000 

$1.46 

1.96 

2.36 

2.80 

3.90 

No.  5435 


No.  5437 


No.  6460 


No.  6457  No.  6469  No.  5460  No.  6462 


No.  6446 


Nos.  6472  and  6472A 


440 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


3886 

6477 

6478 

6479 

6479 A 

6480 


5482 


6484 


•  > 


Furnace  Open  Ready 
for  the  Introduc¬ 
tion  of  a  Tube 

No.  6480 


No.  6479 


Nos.  6482  and  6484 


FURNACE,  COMBUSTION,  four  burners  with  air  regulators,  stopcocks,  and  wing  tops.  With  sup¬ 
port  and  trough  for  heating  tubes.  Complete  as  illustrated,  Page  420  . $9.25 

FURNACE,  CRUCIBLE,  for  illuminating  gas.  Consists  of  a  simple  pot  for  holding  the  crucible,  wdth 
a  lid  and  a  blowpipe  all  mounted  on  a  suitable  cast  iron  base.  Takes  No.  00  Clay  or  Lead 
Crucibles.  Clay  parts,  outside,  measure  \]/2  X  5%  inches  high.  Pot,  inside,  measures  2% 
inches  X  2 x/2  inches  deep.  Furnace  on  stand  is  6 x/2  inches  high  over  all. 

Without  Foot  Blower,  but  complete  with  No.  00  Clay  Crucible . .  3.60 

FURNACE,  CRUCIBLE,  similar  to  above  but  with  Injector  Gas  Burner.  Operates  with  illuminating 
gas,  natural  gas  or  gasoline  gas.  Takes  No.  00  Clay  or  Lead  Crucibles.  Clay  parts,  outside, 
measure  4 }/%  inches  X  5%  inches  high.  Pot  inside,  measures  2%  inches  X  2 Y  inches  deep. 
Furnace  on  stand  is  6Y  inches  high  over  all. 

Without  Foot  Blower,  but  complete  with  one  No.  00  Clay  Crucible .  4.60 

FURNACE,  CRUCIBLE  AND  MUFFLE.  Operates  with  illuminating  gas,  natural  gas  or  gasoline 
gas.  Takes  muffle  3x/2  X  2 Y%  X  6J4  inches  and  No.  3  Clay  or  Lead  Crucible  (3%  inches  diameter 
X  4  inches  high).  Pot  and  cover,  outside,  measures  9%  inches  X  11  inches  high;  inside,  6% 
inches  deep  X  6  inches  diameter. 

Without  Blower,  but  complete  with  Muffle  and  Clay  Crucible . 12.50 

PLUMBAGO  MUFFLE,  3}/2  X  2%  X  6J4  inches .  1.90 

FURNACES,  TUBE  for  combustions.  Using  the  ordinary  foot  blower,  this  furnace  will  heat  an  iron 
tube  %  to  1  inch  in  diameter,  to  its  softening  point  in  ten  minutes.  Without  the  blast  it  will  heat 
the  same  tube  to  redness.  Can  be  used  with  natural  gas,  coal  gas  or  gasoline  gas. 

a  b  c 

For  tubes  of  length,  inches  12  18  24 

Each  $12.76  16.25  19.50 

FURNACES,  ELECTRIC,  CRUCIBLE,  for  work  up  to  1000°  C.  (1832°  F.).  Operates  on  110  or  220 
Volt  A.  C.  or  D.  C.  The  heating  element  of  “Chromel”  wire  is  wound  on  an  alundum  core,  sur¬ 
rounded  by  a  packing  of  special  heat  insulating  material,  enclosed  in  a  sheet  iron  case.  The  maximum 
working  capacity  is  1000°  C.  (1832°  F.)  and  by  means  of  a  controlling  rheostat  should  be  kept  within 
this  limit. 

With  wire  stand  for  using  in  a  horizontal  position,  but  without  Controlling  Rheostat. 

a  b  c 

2  4  5 

2Y2  4  5 

300  900  1100 

$20.00  44.50  66.76 

FURNACES,  ELECTRIC  CRUCIBLE,  same  as  above,  complete  with  wire  stand  for  using  in  a  hori 
zontal  position  and  with  Controlling  Rheostat. 

a  b  c  i 

2  4  5 

2x/2  4  5 

300  900  1 100 

$26.60  64.00  76.00 


Chamber,  Diameter,  inches 
Chamber,  Depth,  inches 
Current  Consumption,  watts 
Each 


Chamber,  Diameter,  inches 
Chamber,  Depth,  inches 
Current  Consumption,  watts 
Each 


REPAIR  PARTS.  PRICES  ON  APPLICATION. 


Nos.  5510  to  6513 

C.  (1832°  F.).  Operates  on  1 10  or  220  Volts 


Nos.  5494  and  5496 

5494  FURNACES,  ELECTRIC  MUFFLE,  for  work  up  to  1000 
A.  C.  or  D.  C. 

The  heating  unit  of  “Chromel”  wire  is  wound  on  an  alundum  muffle  surrounded  by  a  packing  of  special 
heat  insulating  material,  enclosed  in  a  sheet  iron  case.  The  maximum  working  capacity  is  1000°  C. 
(1832°  F.)  and  by  means  of  a  controlling  rheostat,  should  be  kept  within  this  limit. 

Without  Controlling  Rheostat  abed 

Chamber,  Length,  inches  5  8  9  11 

Chamber,  Width,  inches  3^g  4^  5%  7 ]/2 

Chamber,  Height,  inches  2 1/2  3  3 z/± 

Current  Consumption,  watts  650  1100  1800  3300 

Price,  110  or  220  Volts,  A.  C.  or  D.  C.  $44.60  56.00  72.50  100.00 

Note: — When  ordering,  specify  Line  Voltage  and  whether  A.  C.  or  D.  C. 

5496  FURNACES,  ELECTRIC  MUFFLE,  same  as  above,  with  Controlling  Rheostat. 

abed 

Chamber,  Length,  inches 
Chamber,  Width,  inches 
Chamber,  Height,  inches 
Current  Consumption,  watts 
Price,  110  or  220  Volts,  A.  C.  (60  Cycle)  or  D.  C. 

Note: — When  ordering,  specify  Line  Voltage,  and  whether  A.  C.  or  D.  C. 

REPAIR  PARTS  AND  CHARGES 

Immediate  renewals  can  be  made  easily  with  the  repair  parts  listed  below. 

6600  ALUNDUM  MUFFLE  for  Furnace  Nos.  5494a  and  5496a . 

5500A  - ,  wound,  ready  for  use . 

5501  ALUNDUM  MUFFLE  for  Furnace  Nos.  6494b  and  6496b . 

6501A  - ,  wound,  ready  for  use . 

5502  ALUNDUM  MUFFLE  for  Furnace  Nos.  6494c  and  6496c . 

5502A  - ,  wound  ready  for  use . 

6503  ALUNDUM  MUFFLE  for  Furnace  Nos.  5494d  and  5496d . 

5503A  - ,  wound  ready  for  use . 

6504  CHROMEL  WIRE  for  Furnace  Nos.  5494a  and  5496a . Lot 

6606  ,  for  Furnace  Nos.  5494b  and  5496b  .  . . Lot 

6606  ,  for  Furnace  Nos.  6494c  and  5496c . Lot 

6607  ,  for  Furnace  Nos.  5494d  and  5496d . Lot 

6510  FURNACE,  ELECTRIC  TUBE,  for  work  up  to  1000°  C.  (1832°  F.  ).  Operates  on  110  or  220  Volts 

A.  C.  or  D.  C. 


5 

8 

9 

11 

3V8 

4^ 

5H 

7  Vt 

iy2 

3 

3 M 

5  H 

650 

1100 

1800 

3300 

$52.25 

66.00 

85.75 

122.60 

The  heating  unit  of  “Chromel”  wire  is  wound  on  an  alundum  tube,  surrounded  by  a  packing  of  special 
heat  insulating  material,  enclosed  in  a  sheet  iron  case.  The  maximum  working  capacity  is  1000°  C. 
(1832°  F.)  and,  by  means  of  a  controlling  rheostat,  should  be  kept  within  this  limit.  Chamber  iy 
inches  diameter  by  12  inches  long.  Current  consumption  500  watts.  Without  Controlling  Rheo¬ 
stat  . 

6611  - ,  chamber  1J4  inches  diameter  by  12  inches  long.  Current  consumption  500  watts . 

6512  FURNACE,  ELECTRIC  TUBE,  same  as  No.  6510  but  with  Controlling  Rheostat . 

6513  -  — ,  same  as  No.  6611,  but  with  Controlling  Rheostat . . 

REPAIR  PARTS  AND  CHARGES 


Immediate  renewals  can  be  made  easily  with  the  repair  parts  listed  below. 


5516  ALUNDUM  TUBE  for  Furnace  Nos.  6510  and  5512 . 

6515A  - ,  wound  ready  for  use . 

6516  ALUNDUM  TUBE  for  Furnace  Nos.  6511  and  5613 . 

5516A  - ,  wound  ready  for  use . 

6517  CHROMEL  WIRE  for  Furnace  Nos.  6510  and  5612 . Lot 

6618  - ,  for  Furnace  Nos.  5511  and  6613 . Lot 


$2.75 

10.00 

4.60 

16.00 

5.75 

20.00 

7.75 
31.60 

2.75 
4.50 

6.75 
11.25 


27.75 

27.75 

36.00 

36.00 


2.35 

7.75 

2.50 

7.75 

2.25 

2.25 


442 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


5620 


5522 


6525 

5526 

5527 

5630 


5530A 

5533 


6533A 

5535 

653 5 A 
5537 

6637A 


5540 

5541 

5542 
6543 


Nos.  6520  and  5622 


Nos.  6630  to  6637 


FURNACES,  ELECTRIC  CRUCIBLE,  for  work  requiring  temperatures  up  to  1100°  C.  (2000°  F.)  for 
use  on  alternating  current  only. 

The  heating  unit  is  of  “Chromel”  wire  wound  in  the  form  of  a  core  which  radiates  heat  directly  on 
the  contents  of  the  furnace.  Surrounding  the  heating  unit  is  a  layer  of  special  fire  brick  heat  insu¬ 
lation,  and  outside  of  this,  a  sheet  iron  case. 

These  furnaces  operate  on  low  voltages  (10  to  57  volts)  and  as  regularly  supplied  for  110,  220  or  440 
volts  (60  cycles)  circuit,  require  a  transformer  and  controlling  rheostat. 

a  b  c 

Diameter,  Chamber,  inches  1)4  2  4 

Depth,  Chamber,  inches  1)4  2)4 

Current  Consumption,  watts  650  1000  2000 

Price,  110,  220  or  440  volts  (60  cycles)  A.  C.  $44.60  49.00  122.00 

Note: — When  ordering  specify  Line  Voltage. 

FURNACES,  ELECTRIC  CRUCIBLE,  same  as  above,  but  Furnace  only,  without  Transformer  and 
Controlling  Rheostat.  a  b  c 

Diameter,  Chamber,  inches  1)4  2  4 

Depth,  Chamber,  inches  1 %  2)4  6 

Current  Consumption,  watts  650  1000  2000 

Price,  1 10,  220  or  440  volts  (60  cycles)  A.  C.  $20.00  22.25  67.60 

Note: — When  ordering  specify  Line  Voltage. 

EXTRA  HEATING  UNITS 

When  not  heated  above  1100°  C.  (2000°  F.),  the  life  of  a  heating  unit  should  be  at  least  1000  hours. 
By  having  at  hand  extra  heating  units,  immediate  repairs  can  be  made  by  the  operator. 

EXTRA  HEATING  UNIT  for  Furnace  Nos.  6620a  and  6622a  .  > . 

- ,  for  Furnace  Nos.  5520b  and  5522b . . . 

- ,  for  Furnace  Nos.  5520c  and  6522c . , . 


$3.35 

4.50 

9.00 


FURNACE,  ELECTRIC  MUFFLE,  for  work  up  to  1 100°  C.  (2000°  F.)  for  use  on  alternating  current 
only. 

The  heating  unit  is  in  the  shape  of  heavy  hair  pins  which  are  distributed  around  the  top,  bottom  and 
sides  of  a  refractory  muffle.  Surrounding  the  heating  units  is  a  layer  of  special  fire  brick  heat  in¬ 
sulation  and  outside  of  this,  a  sheet  iron  case. 

This  furnace  operates  on  low  voltage  and  as  regularly  supplied,  for  110,  220  or  440  volts  (60  cycles) 
circuits,  requires  a  transformer  and  a  controlling  rheostat. 

Chamber  4)4  inches  wide,  3  inches  high,  9  inches  long.  Current  consumption  2750  watts. 


Complete  with  Transformer  and  Controlling  Rheostat . 130.00 

- ,  same  as  above,  but  Furnace  only,  without  Transformer  and  Controlling  Rheostat . 67.50 

FURNACE,  ELECTRIC  MUFFLE,  same  as  No.  5530,  but  designed  so  that  temperature  regulation  is 
secured  by  regulating  transformer. 

This  furnace  is  also  mounted  on  an  angle  iron  stand  that  brings  the  shelf  40  inches  above  the  floor. 

Chamber  7)4  inches  wide,  5  inches  high,  12)4  inches  long.  Current  consumption,  6000  watts  .  .  .  212.00 

- ,  same  as  above,  but  Furnace  only,  without  Regulating  Transformer . 106.00 

FURNACE,  ELECTRIC  MUFFLE,  same  as  No.  5530,  but  chamber  12  inches  wide,  8  inches  high,  19 

inches  long.  Current  consumption  12,500  watts.  With  Regulating  Transformer .  476.00 

- ,  same  as  above,  but  Furnace  only,  without  Regulating  Transformer .  280.00 

FURNACE,  ELECTRIC  MUFFLE,  same  as  No.  6630,  but  chamber  12  inches  wide,  8  inches  high,  26 

inches  long.  Current  consumption  15,000  watts.  With  Regulating  Transformer .  640.00 

- ,  same  as  above,  but  Furnace  only,  without  Regulating  Transformer .  335.00 

Note: — When  ordering  any  of  the  above  Muffle  Furnaces,  specify  Line  Voltage. 

EXTRA  HEATING  ELEMENTS 


When  not  heated  above  1100°  C.  (2000°  F.)  the  life  of  a  heating  unit  should  be  at  least  1000  hours. 

By  having  at  hand  extra  heating  units,  immediate  repairs  can  be  made  by  the  operator. 

EXTRA  HEATING  UNITS  for  Furnace  No.  6630  (10  per  set) . Each  Unit 

- ,  for  Furnace  No.  5533  (10  per  set) . Each  Unit 

- ,  for  Furnace  No.  5535  (14  per  set) . Each  Unit 

- ,  for  Furnace  No.  6537  (14  per  set) . Each  Unit 


1.16 

2.25 

3.35 

4.50 


CHEMISTRY  AND  BIOLOGY 


443 


Nos.  5545  to  5548 


5545  FURNACE,  ELECTRIC  TUBE  for  work  up  to  1100°  C. 

(2000°  F.)  for  use  on  alternating  circuits  only,  110,  220 
or  440  volts  (60  cycles). 

The  heating  unit  is  of  “Chromel”  wire,  in  the  form  of 
a  coil  which  radiates  heat  directly  on  the  contents  of 
the  furnace. 

Surrounding  the  heat  unit  is  a  layer  of  special  fire  brick 
heat  insulation,  and  outside  of  this,  a  sheet  iron  case. 

The  temperature  regulation  is  by  means  of  a  control¬ 
ling  rheostat. 

Diameter  of  chamber,  1  inch,  length,  11  inches.  Current 

consumption  1000  watts.  With  Controlling  Rheostat  $60.00 


6646  -  — ,  same  as  above,  but  Furnace  only,  without  Con¬ 

trolling  Rheostat . 33.50 

6647  FURNACE,  ELECTRIC  TUBE,  same  as  No.  6645,  but 

diameter  of  chamber  1)4  inches,  length  11  inches. 
Current  consumption  1000  watts.  With  Controlling 
Rheostat . 60.00 

6648  - ,  same  as  above,  but  Furnace  only,  without  Con¬ 

trolling  Rheostat . 33.60 


REPAIR  PARTS 

When  not  heated  above  1100°  C.  (2000°  F.)  the  life  of  the  heating  unit  should  be  at  least  1000  hours. 
By  having  at  hand  extra  heating  units,  immediate  repairs  can  be  made  by  the  operator. 


5660  EXTRA  HEATING  COIL  for  Furnace  No.  6645 


4.60 


6661  - ,  for  Furnace  No.  6647 


4.60 


ELECTRIC  FURNACE  CORES 


6566  FURNACE  CORES,  ELECTRIC,  ALUNDUM.  Alundum  Refractory  Cores  have  -high  heat  conduc¬ 
tivity  and  do  not  become  electrical  conductors  when  at  the  highest  temperature  obtained  in  the  fur¬ 
nace.  The  wires  should  be  protected  by  embedding  them  in  Alundum  Cement.  Thus  fully  pro¬ 
tected,  they  do  not  corrode  under  the  most  severe  conditions,  since  the  alundum  mixtures  are  chemi¬ 
cally  inert. 


Bore,  inches 
Length,  inches 
Pitch,  inch 
Both  Ends  Open 
One  End  Closed 


a 

b 

c 

d 

e 

f 

g 

h 

i 

1 

l  H 

2 

2% 

2H 

2X 

3 

3 

3  Vi 

10 

12 

10 

2% 

2% 

5 

7 

24 

5 

Vi* 

% 

V» 

A 

% 

X 

% 

Vi 

% 

$4.26 

4.60 

4.60 

$1.76 

1.15 

2.25 

4.60 

13.60 

4.60 

] 

5 

9 

% 


k 

5 

12 

X 

7.26 


6.76 


444 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


FURNITURE 


No.  6575 


5575  STUDENTS’  COMBINATION  BIOLOGY  TABLE.  The  table  illustrated  is  made  up  from  four  dif¬ 
ferent  units,  —  the  table  proper,  two  bottle  racks  and  the  case  of  drawers. 

Table  Proper.  Body  constructed  of  selected  solid  oak  with  top  of  selected  narrow  strips  of  kiln-dried 
maple,  machined,  matched  and  glued  in  a  manner  to  prevent  warping.  A  dividing  strip  runs  length¬ 
wise  on  the  top  through  the  center.  Length,  6  feet,  width,  3  feet,  height,  30  inches. 

Bottle  Racks.  One  at  each  end  is  of  unit  construction  and  may,  if  desired,  be  added  to  the  table  proper 
at  any  time.  It  provides  three  shelves,  the  two  lower  being  4  inches  apart.  These  racks  will  be 
found  most  convenient. 

Case  of  Drawers.  The  case  is  designed  to  slide  under  the  aprons  and  to  extend  front  to  back  flush  with 
the  aprons.  The  sides  are  panelled  and  ends  provided  with  four  drawers.  Width  over  all,  15  inches; 
height  over  all,  about  24  inches. 

Complete  with  Case  of  Drawers  and  two  Bottle  Racks . $48.00 

5575A  STUDENTS’  BIOLOGY  TABLE,  plain,  same  as  above,  but  without  Case  of  Drawers  and  without 

Bottle  Racks . 21.00 

5575B  CASE  OF  DRAWERS  for  use  with  above  table  and  as  described  under  No.  5675  .  22.00 

5575C  BOTTLE  RACKS  for  use  on  above  or  any  table,  and  as  described  under  No.  6575  . Each  4.50 


n 


No.  5680 

5580  BIOLOGY  LECTURE  TABLE,  length  over  all,  feet,  width,  3  feet,  height,  34  inches. 

The  body  of  table  is  constructed  of  selected  kiln-dried  solid  oak,  the  top  of  narrow  strips  of  straight 
grained  maple,  machined,  matched  and  glued  in  a  manner  to  prevent  warping. 

The  front  and  ends  are  panelled,  the  back  provided  with  a  cupboard  at  each  end  and  two  large  and 
two  small  drawers  and  a  drop  front  compartment  over  the  drawers  between.  The  compartment  over 
the  drawers  is  intended  for  dissecting  boards,  large  drawings,  charts,  etc. 

The  sink  is  of  heavy  construction,  lined  with  sheet  lead.  It  measures,  inside,  22  X  20  X  12  inches 
deep  and  is  fitted  with  a  standing  overflow  10}^  inches  high  and  with  flush  cover. 

We  supply  our  Triple  Interchangeable  Nozzle  Goose-neck  Faucet  for  water  supply  and  our  Four¬ 
way  Gas  Turret  with  Lever  Handle  Serrated  End  Gas  Cocks  for  gas  supply. 

The  top  is  treated  and  carbonized  to  make  acid  and  alkali-proof.  The  body  is  finished  in  standard 
light  antique  color. 

Without  cocks . F.  O.  B.  Factory  $140.00 


For  AQUARIUM  for  this  table,  if  desired,  see  No.  3527,  Page  406. 


CHEMISTRY  AND  BIOLOGY 


445 


No.  1-726  No.  1-700 


No.  1-760 


No.  6606 


No.  6590A 


No.  6690B 


6690  GAS  APPARATUS  for  sulphur  determinations,  according  to  Mr.  C.  D.  Jenkins,  Massachusetts  State 


Inspector  of  Gas  and  Meters . $12.60 

5590A  GAS  SAMPLE  TUBES,  according  to  Mr.  C.  D.  Jenkins .  1.00 

6690B  GAS  AMMONIA  BULBS,  according  to  Mr.  C.  D.  Jenkins .  1.00 

6693  GAS  BAGS,  pure  gum  rubber,  without  stopcock.  a  b 

Capacity,  quarts  4  8 

Each  $2.18  2.66 

6694  GAS  STOPCOCK  for  use  on  above  GAS  BAGS . 70 

6697  GAS  BOTTLE  GENERATOR,  capacity  32  ounces,  complete  with  fittings .  .90 


KNOTT’S  GAS  COCKS 

The  Knott  Gas  Cocks  are  of  brass.  The  nipples  are  long,  and  with  five  sharp  serrations  which  make  it  easy 
to  slip  on  rubber  tubing,  but  impossible  to  pull  it  off  accidentally.  Adjustment  is  secured  by  means  of  a  lever 
handle. 

1-700  KNOTT’S  LEVER  HANDLE  GAS  COCK,  J^-inch  I.  P .  $0.66 

1-710  KNOTT’S  SINGLE  GAS  TURRET,  one  gas  cock .  1.46 

1-716  KNOTT’S  TWO-WAY  GAS  TURRET,  two  gas  cocks .  1.86 

1-720  KNOTT’S  THREE-WAY  GAS  TURRET,  three  gas  cocks .  2.26 

1-726  KNOTT’S  FOUR- WAY  GAS  TURRET,  four  gas  cocks .  2.66 

1-760  THE  KNOTT  MOUNTED  FOUR-WAY  GAS  TURRET.  The  use  of  this  design  obviates  all  necessity 
of  cutting  a  table  top.  It  is  connected  by  rubber  tubing  to  a  supply  cock  left  at  the  floor  line  or 
above  the  table .  4.60 

6606  GAS  COLLECTOR  (Beehive  Shelf)  of  unglazed  porcelain,  2%  inches  high,  for  use  in  a  sink  or  dish  as 

the  bottle  rest  for  collecting  gases  over  water .  .30 

6607  GAS  COLLECTOR  (Packard’s  Glazed  Porcelain  Beehive  Shelf).  This  collector  is  provided  with  a 

recessed  top  for  holding  the  neck  of  the  bottle,  and  since  it  is  but  one  inch  high,  requires  very  little 

water,  thus  permitting  the  use  of  a  shallow  dish.  Excellent  for  lecture  desk . 18 

6610  GAS  GENERATOR,  GASOLINE,  constructed  wholly  of  brass,  polished  and  nickeled.  Height  7 
inches,  diameter  4 Yi  inches.  Interior  contains  14  lineal  feet  of  evaporating  surface.  Turret  valve 
at  top  controls  both  gas  and  air  outlets,  also  controls  the  size  of  the  blowpipe  flame.  Built  absolutely 
proof  against  any  danger  of  flashing  back  of  the  flame.  An  air  check  is  attached  at  the  end  of  the  filler 
tube  to  prevent  over  filling.  Complete  as  illustrated .  9.76 

6612  GAS  GENERATOR,  OXYGEN,  of  polished  metal,  inches  high,  weighing  but  lYi  pounds.  Ca¬ 

pacity  at  one  charge  27  liters,  —  nearly  one  cubic  foot.  The  charge  consists  of  an  “Oxone  Cart¬ 
ridge,”  a  hermetically  sealed  tin  which  is  to  be  punctured  on  top  and  bottom. 

Produces  pure  oxygen  instantaneously.  This  oxygen  is  at  low  pressure  and  as  it  leaves  the  generator 
is  99.3  per  cent.  pure.  As  it  leaves  the  wash  bottle  it  is  considered  100  per  cent,  pure  oxygen. 

Simple  and  easy  to  handle,  quickly  recharged  and  always  a  source  for  obtaining  pure  oxygen  instantly. 
Complete  outfit  is  packed  in  a  finished  portable  case  and  comprises  the  generator  with  wash  bottle, 

awl  for  perforating  the  tin,  four  oxone  cartridges  and  rubber  tubing  lead . 20.00 

Note:  —  The  above  outfit,  using  “Hydrone”  in  place  of  “Oxone,”  may  be  used  to  generate  pure 
hydrogen. 

6613  “OXONE”  CARTRIDGES,  sold  only  in  two  pound  tins . Per  Tin  1.60 

6614  “HYDRONE”  CARTRIDGES,  sold  only  in  two  pound  tins . Per  Tin  1.60 


446 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6620 


L!ikl4iliniBnMT 


No.  6616  No.  12-296 

6616  GAS  HOLDER,  Gasometer,  Berzelius’  and  Pepy’s,  improved  form,  of  heavy  copper.  Capacity, 

5  gallons . $19.60 

6617  - ,  capacity  10  gallons . 24.60 

5620  GAS  MEASURING  TUBES  for  collecting  gases  over  mercury.  Subdivided  by  cc. 

a  b 

Capacity,  cc.  50  100 

Each  '  $1.46  1.80 

6626  GAS  PRESSURE  REGULATOR,  Murrill’s  Improved,  for  use  with  a  thermostat.  A  constant  tem¬ 
perature  can  be  maintained  regardless  of  the  pressure  variations  in  the  gas  supply.  With  two  out¬ 
lets  as  illustrated .  $9.76 

6626  GAS  REGULATOR,  Reichert’s,  adapted  for  water  baths,  drying  ovens,  incubators,  sterilizers,  etc. 

Secures  constant  temperature  at  any  desired  point  from  1°  C.  up  to  the  boiling  point  of  mercury  3.25 
6628  GAS  REGULATOR,  Roux  Bi-metallic,  an  accurate  gas  regulator,  simple  in  construction,  easily  oper¬ 
ated  and  adjusted  to  regulate  an  even  temperature  more  constantly  than  any  other  thermo-regu¬ 
lator.  Not  liable  to  leak  as  it  is  made  entirely  of  metal.  Particularly  well  adapted  for  ovens  and 

sterilizers.  Length  10  inches.  Complete  with  directions .  8.60 

5629  GAS  REGULATOR,  Roux  Bi-metallic.  Same  as  above,  but  for  high  temperatures .  9.76 

GAS  STOVES.  See  STOVES,  Pages  483  and  484. 

12-295  GAUGE,  POLISHED  STEEL,  INSIDE  TAPER,  for  inside  measure  of  tubes,  holes,  etc.  Made  of 

hardened  polished  steel  and  about  18  centimeters  long.  Will  measure  from  to  15  millimeters  .80 
6632  GAUZE,  ASBESTOS  CENTER,  tinned  iron  wire,  5X5  inches  with  asbestos  compressed  in  the 

mesh.  Excellent  for  slow  evaporations . Each  .10 

6634  GAUZE,  COPPER,  thick  wire,  mesh  selected  for  use  in  heating  chemical  ware. 

a  b  c 

Size,  inches  4X4  6X6  12X12 

Each  $0.10  .20  .70 

6636  GAUZE,  COPPER,  80  mesh,  4X4  inches . 18 

6637  GAUZE,  IRON,  thick  wire,  mesh  selected  for  use  in  heating  chemical  ware. 

a  b  c 

Size,  inches  4X4  6X6  12X12 

Each  $0.04  .07  .27 

GENUS  COVERS.  See  Page  472. 

3636  GLASS,  LECTURE,  for  use  on  lecture  desk  for  a  large  class  of  chemical  experiments.  Capacity  350 

cc.  (For  illustration  see  Page  412) . 60 

6642  GLASSES,  TEST,  on  foot,  clear  colorless  glass. 

a  b 

Capacity,  ounces  2  4 

Each  $0.40  .46 

3616  GLASS  BEADS,  hollow,  for  filtering  or  drying  gases  by  means  of  acid . Per  Pound  .95 


CHEMISTRY  AND  BIOLOGY 


447 


6645 

5646 

6649 

5650 

5651 
5653 


6330 


6482 


No.  5653  No.  6095  No.  5098 

GLASS  BLOWERS’  FIRES.  See  BLOWPIPES,  Page  416. 

GLASS  CUTTER,  single  steel  wheel,  with  metal  handle . $0.07 

GLASS  CUTTER,  TURRET  HEAD.  Turret  contains  six  high  grade  steel  wheels,  hardened  and  tem¬ 
pered  and  carefully  tested.  Ebony  finished  handle,  nickeled  ferrule,  highly  polished .  .30 

GLASS  CUTTING  DIAMOND,  excellent  quality .  6.40 


GLASS  TUBE  CUTTER,  BUNSEN’S,  a  practical  tool  with  steel  wheel,  hardened  and  tempered  .  .  . 
GLASS  TUBE  CUTTER  for  tubes  up  to  j^-inch  diameter,  inexpensive  but  efficient,  rapid  and  practical 
GLASS  CUTTER  FOR  CIRCLES.  Cuts  circles  from  2J4  to  22^4  inches  in  diameter.  Cutter  head 
is  interchangeable,  allowing  for  renewing  of  cutters,  and  is  secured  firmly  to  the  graduated  rod 

Hardwood  handles  and  base  with  felt  covered  bottom 

b  c 

5X5  6X6 

.04  .05 


marked  to  ]/%  inches.  All  parts  nickel-plated. 
GLASS  PLATES  for  covers.  a 

Size,  inches  4X4 

Each  $0.03 

GLASS  RODS.  See  RODS,  GLASS,  Page  477. 
GLASS  RODS,  stirring  rods,  finished  ends. 

Size,  mm. 

Per  Dozen 


GLASS  TUBING.  See  TUBING,  GLASS,  Page  491 


a 

X  150 

$0.16 


b 

X  150 

.20 


6660 

GLASS  WOOL  for  filtering  acids,  etc.  .  .  . 

Per 

ounce 

5662 

GOLD  BEATERS’  SKIN  .  . 

5664 

GRADUATES,  conical,  graduated  in  ounces. 

a 

b 

c 

d 

e 

f 

g 

Capacity,  ounces 

Vi 

1 

2 

4 

8 

16 

32 

Each 

$0.20 

.22 

.25 

.30 

.50 

.70 

1.10 

5666 

GRADUATES,  conical,  graduated  in  cubic  centimeters. 

a 

b 

c 

d 

e 

f 

Capacity,  cc. 

30 

60 

100 

250 

500 

1000 

Each 

$0.25 

.28 

.32 

.55 

.81 

1.25 

6667 

GRADUATES,  conical,  graduated  in  both  ounces  and  cubic  centimeters. 

a  b 

c 

d 

e 

f 

Capacity,  ounces  1  2 

4 

8 

16 

32 

Capacity,  cc.  30  60 

125 

250 

500 

1000 

Each  $0.30  .36 

.46 

.66 

1.00 

1.66 

6095  GRADUATES,  CYLINDRICAL,  of  glass,  broad  base,  with  lip,  graduated  in  cubic  centimeters. 

a  b  c  d  e  f  g 

Capacity,  cc.  10  25  50  100  250  500  1000 

Each  $0.30  .36  .40  .62  .90  1.10  1.86 

6096  GRADUATES,  CYLINDRICAL,  double  graduations,  reading  up  and  down,  of  glass,  broad  base,  with 

lip,  graduated  in  cubic  centimeters.  a  b  c  d  e  f 

Capacity,  cc.  25  50  100  250  500  1000 

Each  $0.38  .45  .56  .96  1.20  2.00 

6098  GRADUATES,  MIXING,  STOPPERED,  serviceable  when  making  standard  solutions.  Of  glass,  broad 
base,  round  glass  stoppers,  graduated  in  cubic  centimeters. 

a  b  c  d  e  f  g 

Capacity,  cc.  25  50  100  200  250  500  1000 

Each  $0.75  .85  .96  1.20  1.30  1.85  2.25 


.60 

.30 


1.35 


.60 

.10 


448  L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6671 


HEATER,  ELECTRIC,  WATER.  See  ELECTRIC  APPLIANCES,  Page  436. 

HEATERS,  SOLDERING  IRON.  See  SOLDERING  IRON  HEATERS,  Page  479. 

HOT  PLATES.  See  STOVES,  Pages  483  and  484,  and  BATHS,  SAND,  Page  409. 

HYDROMETERS 

Our  line  of  hydrometers  has  been  selected  with  unusual  care  to  cover  the  requirements  not  only 
of  commercial,  but  also  of  educational  laboratories  as  well.  We  believe  tve  have  covered  general 
requirements.  We  most  respectfully  solicit  correspondence  relative  to  special  individual  requirements 
which  are  not  met  in  the  following  listings. 


31-170  HYDROMETER  for  light  liquids,  double  scale,  Beaume,  70  to  10,  Specific  Gravity, 

0.7000  to  1.000  . $0.60 

31-171  HYDROMETER  for  heavy  liquids,  double  scale,  Beaume,  0-70,  Specific  Gravity,  1.000 

to  2.000  . 60 

31-176  HYDROMETER,  Specific  Gravity  Scale  onlv,  for  both  light  and  heavy  liquids.  Range 

0.7000  to  2.000  .  1.26 

6668A  HYDROMETER,  Twaddle  Scale,  0°  to  24°,  x/2°  graduation .  .86 

6668B  ,  24°  to  48°,  x/2°  graduation .  .86 

6668C  ,  48°  to  72°,  j^°  graduation .  .86 

6668D  ,  72°  to  100°,  y2°  graduation . 86 

6668E  ,  100°  to  134°,  x/2°  graduation .  .86 

6668F  - ,  134°  to  180°,  y2°  graduation . 86 

6669A  HYDROMETER,  Specific  Gravity  scale,  0.600  to  0.700,  .02°  graduation .  1.00 

6669B  - ,  0.700  to  0.800,  .02°  graduation . .  .  1.00 

6669C  ,  0.800  to  0.900,  .02°  graduation .  1.00 

6669D  ,  0.900  to  1.000,  .02°  graduation .  1.00 

6669E  ,  1.000  to  1.200,  .05°  graduation . 1.00 

6669F  ,  1.200  to  1.400,  .05°  graduation .  1.00 

6669G  ,  1.400  to  1.600,  .05°  graduation .  1.00 

6669H  ,  1.600  to  1.800,  .05°  graduation .  1.00 

56691  ,  1.800  to  2.000,  .05°  graduation .  1.00 

6670A  HYDROMETER,  Beaume  Scale,  coal  oil  hydrometer,  10°  to  50°,  1°  graduation  ...  .76 

6670B  ,  40°  to  70°,  1°  graduation  . . 75 

5670C  ,  60°  to  100°,  1°  graduation . 76 

6671  HYDROMETER  for  storage  batteries,  consisting  of  the  hydrometer  proper  inside  a 

glass  tube  with  a  rubber  bulb  at  the  top  and  a  rubber  tube  at  the  bottom.  The 
rubber  tube  may  be  inserted  in  the  storage  battery,  a  quantity  of  acid  withdrawn 
into  the  glass  tube,  the  reading  taken  and  the  liquid  replaced  within  a  few  seconds, 
and  with  great  convenience.  Outfit  complete .  1.66 

6672  HYDROMETER,  similar  to  the  one  used  in  the  above  set,  scale  1.150°  to  1.300°, 

.005°  graduation.  Length  about  5  inches.  With  test  jar  in  wooden  case  ....  .76 

6136  LACTOMETER,  Spence’s,  New  York  Board  of  Health  pattern,  0°  to  120°,  2°  graduation  1.00 

6137  LACTODENSIMETER,  Quevenne’s  Pattern,  scale  15°  to  40°  (1.015  to  1.040  Specific 

Gravity),  1°  graduation .  1.00 


5673A  ALCOHOLOMETER,  Proof  Scale,  50°  below  proof  to  0°  (proof),  1°  graduation .  1.00 

5673B  ALCOHOLOMETER,  Proof  and  Tralle  Scale,  100°  below  to  100°  above  proof;  0°  to  100°  Tralle; 

1°  graduation .  1.00 

5674A  HYDROMETER,  for  Sugar,  Brix  scale,  0  to  30°,  x/2°  graduation .  1.00 

5674B  - ,  30°  to  60°,  y2°  graduation . .  1.00 

5674C  - ,  60°  to  90°,  y2  graduation .  1.00 

31-250  HYDROMETER  JARS  or  CYLINDERS,  of  clear  white  glass,  with  foot  and  rim. 


a  b  c  d  e 

Size,  inches  12  X  1 H  12  X  2  15  X  2  15  X  3  18  X  3 

Each  $0.60  .66  .80  1.00  1.35 

HYPERDERMIC  SYRINGE.  See  SYRINGE,  HYPERDERMIC,  Page  486. 


.. 


V 


•••*#*»■>'  -^v?  i  nr-v  ■  ■*. 


CHEMISTRY  AND  BIOLOGY 


449 


INCUBATORS 


Nos.  6680  and  6682  No.  6683 


6680  INCUBATOR,  POLISHED  COPPER,  double  wall,  sheet  iron  base  9  inches  high,  —  otherwise  the  same 
as  the  Triple  Wall  Incubators  Nos.  6686  to  6688.  Inside  dimensions  10  inches  high,  8  inches  wide, 
8  inches  deep;  outside,  13  inches  high,  113-6  inches  wide,  113-6  inches  deep.  With  one  shelf  .... 

6682  INCUBATOR,  POLISHED  COPPER,  double  wall,  same  as  above,  but  inside  dimensions,  12  inches 

high,  10  inches  wide,  10  inches  deep;  outside,  15  inches  high,  133-6  inches  wide,  133-6  inches  deep  . 

6683  INCUBATOR,  POLISHED  COPPER,  double  wall,  the  outer  one  covered  with  insulating  material. 
Two-inch  water  space,  water  gauge  and  stopcock.  Base  is  of  sheet  iron  and  is  9  inches  high.  A  glass 

plate  in  the  top  permits  of  examination  of  contents  without  opening  the  top.  Inside  measurements,  8 
X  9  inches;  outside,  12  X  12  inches.  With  one  perforated  tray . 


6685 


INCUBATOR,  POLISHED 
COPPER,  three  wall,  hav¬ 
ing  both  air  and  water 
space,  the  outer  surface 
being  covered  with  insulat¬ 
ing  material  to  insure  an 
even  temperature.  Double 
doors,  the  inner  one  of 
beveled  glass  to  permit  ob¬ 
servation  of  cultures  with¬ 
out  disturbing  the  tem¬ 
perature.  Tubulations  for 
gas  regulator,  thermometer 
and  for  filling  water  space. 

Supported  on  a  sheet  iron 
base,  10  inches  high,  fin¬ 
ished  in  durable  black,  hav¬ 
ing  a  door  with  an  open¬ 
ing  covered  with  mica  for 
observation  of  the  flame. 
Inside  dimensions,  9  inches 
high,  7  inches  wide,  7  inches  . 
deep.  Outside  dimensions, 

13  inches  high,  11  inches 
wide  and  103-6  inches  deep. 

With  one  shelf  ....  $43.76 


Nos.  6686  and  6686 


6686 


INCUBATOR,  POLISHED  COPPER,  three  wall,  having  both  air  and  water  space.  Same  as  above, 
but  inside  dimensions  12  inches  high,  9  inches  wide,  9  inches  deep.  Outside  dimensions,  17  inches 
high,  14  inches  wide,  13  inches  deep.  With  one  shelf . 


$42.60 

52.60 

19.50 


$64.00 


450 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


6687  INCUBATOR,  POLISHED 
COPPER,  three  wall.' 

Same  as  No.  6685,  but  height 
of  base  11  inches  and  inside 
dimensions,  14  inches  high, 

12  inches  wide,  10  inches 
deep.  Outside  dimensions, 

19  inches  high,  17  inches 
wide,  14  inches  deep.  With 
two  shelves . $72.00 


6688  INCUBATOR,  POLISHED 
COPPER,  three  wall.  ' 

Same  as  above,  but  inside 
dimensions,  20  inches  high, 

18  inches  wide,  10  inches 
deep.  Outside  dimensions, 

25%  inches  high,  2 3%  inch¬ 
es  wide,  14%  inches  deep. 

With  two  shelves  ....  98.00 


Nos.  5687  and  5688 


INCUBATORS,  ELECTRICALLY  HEATED  WITH  ELECTRICAL  CONTROL 

Can  be  used  on  Direct  or  Alternating  Current 


The  following  incubators  are  the  same  sizes 
and  have  the  same  points  of  excellence  as  Nos. 
5685  to  5688.  They  are,  however,  built  with  proper 
insulation  for  electrical  heating.  If  at  any  time  it 
should  be  desired  to  use  these  incubators  on  gas, 
the  electric  attachment  may  readily  be  removed. 

The  electric  regulator  is  a  device,  simple  and 
practical  in  construction,  and  one  quite  easily 
operated.  When  once  set,  it  requires  absolutely 
no  attention  and  there  will  hardly  be  a  noticeable 
variation  in  temperature.  Operation  by  expanded 
mercury,  positively  insures  the  finest  adjustment. 

6690  ELECTRIC  INCUBATOR,  9X7x7 

inches,  inside  measurements.  With 
one  shelf . $96.00 

6691  - ,  12  X  9  X  9  inches,  inside 

measurements.  With  one  shelf  .  .  110.00 

5692  - ,  14  X  12  X  10  inches,  inside 

measurements.  With  two  shelves  136.00 

5693  - ,  20  X  18  X  10  inches,  inside 

measurements.  With  two  shelves  165.00 

6700  INK,  DIAMOND,  for  writing  on  glass, 
labeling  bottles,  beakers,  etc.  Per 
ounce . .  .76 

IRON,  ELECTRIC.  See  ELECTRIC 
APPLIANCES,  Page  436. 


Nos.  5690  to  5693 


CHEMISTRY  AND  BIOLOGY 


451 


No.  5717 


a  b  c 
No.  6945 


5705 

5096 


6096 


g 

1000 

1.85 

Of  glass,  broad 


No.  6730  No.  5727  No.  6705 

JARS,  AQUARIA.  See  AQUARIA,  Page  406. 

31-265  JARS,  BATTERY,  of  excellent  quality. 

a  bed 

Size,  inches  2} •i  X  3J4  4X5  6X8  8  X  12 

Each  $0.12  .26  .40  1.50 

91-380  .  JARS,  RECTANGULAR  BATTERY,  of  excellent  quality. 

a  b 

Size,  inches  2lA  X  4 %  X  7  4X4X8 

Each  $0.35  .45 

JAR,  CALCIUM  CHLORIDE  (Drying  Tower).  Clear  white  glass,  10  inches  high . $1.00 

JARS,  GRADUATED,  CYLINDRICAL.  Of  glass,  broad  base,  with  lip,  graduated  in  cubic  centimeters, 
a  b  c  d  e  f 

Capacity,  cc.  10  25  50  100  250  500 

Each  $0.30  .36  .40  .52  .90  1.10 

JARS,  GRADUATED,  CYLINDRICAL,  double  graduations,  reading  up  and  down, 
base,  with  lip,  graduated  in  cubic  centimeters. 

a  b  c  d  e  f 

Capacity,  cc.  25  50  100  250  500  1000 

Each  $0.38  .45  .56  .95  1.20  2.00 

JARS,  GRADUATED,  MIXING,  STOPPERED.  Of  glass,  broad  base,  round  glass  stoppers,  gradu¬ 
ated  in  cubic  centimeters. 

a  b  c  d  e  f  g 

Capacity,  cc.  25  50  100  200  250  500  1000 

Each  $0.75  .85  .95  1.20  1.30  1.85  2.25 

JARS,  HYDROMETER,  of  clear  white  glass,  with  foot  and  rim. 

a  b  c  d  e 

Size,  inches  12  X  1H  12  X  2  15  X  2  15  X  3  18  X  3 

Each  $0.50  .55  .80  1.00  1.35 

JARS,  MUSEUM,  for  preserving  and  displaying  specimens  in  laboratories  and  museums.  Of  clear 
colorless  glass.  Mouth  same  width  as  inside  diameter.  Contents  securely  sealed  by  a  metal  clamp 
which  binds  the  glass  cover  to  jar  with  thin  rubber  gasket  between.  On  the  under  side  of  the  cover 
are  two  glass  rings  from  which  specimens  may  be  suspended. 

abed  e 

Height,  without  Lid,  inches 
Width  of  Mouth,  inches 
Approximate  Capacity,  pints 
Each 

JAR,  STAINING,  COPLIN’S,  for  use  in  staining  sections  for  microscopic  work.  With  glass  lid 

ground  on  shoulder.  For  ten  slides . . 

JARS,  NESSLER,  for  ammonia  tests  in  water  analysis;  of  colorless  glass. . 


5098 


31-260 


5715 


6717 

6945 

5720 

6727 


4 

8 

8 

8 

12 

2H 

2K 

3'A 

5 

5 

h 

1 

2V2 

sy2 

8 

$0.65 

.70 

1.00 

1.90 

2.10 

.36 


5730 


a  b  c 

Graduated,  cc.  50  100  50  and  100 

Each  $0.66  .80  .95 

JARS,  SHOW,  INVERTED,  clear,  colorless  glass. 

a  bed 

H  12  4 

$0.20  .26  .36  .60 

“Lightning  Sealing,”  for  chemical,  biological  and  botanical  specimens, 
a  bed 

X  12  4 

$0.10  .12  .14  .20 

Capacity  3  gallons,  with  cover  and  handles . 


Capacity,  pints 
Each 

JARS,  STORAGE, 


Capacity,  pints 
Each 

JAR,  WASTE,  stoneware. 


.85 


452 


L  .  E.  KNOTT  APPARATUS  CO.,  BOSTON 


6750 


6763 


6758 

6760 

6761 

6766 

6770 


6770A 

6773 

6773A 


6780 

6781 
5782 
6783 
6789 
5796 


No.  6766 

LABELS,  GUMMED,  red  border,  in  boxes. 


No.  5770 


No.  5773 


Trade  No. 

217 

213 

209 

205 

201 

2004 

2007 

2002 

2001 

2006 

2005 

2003 

Length,  inches 

i  1 

134 

134 

134 

234 

234 

3 

334 

3  34 

434 

4  34 

434 

Width,  inches 

34 

1 

134 

m 

134 

l 

134 

134 

134 

134 

2 

2 

Per  Box 

$0.07 

.07 

.07 

.07 

.07 

.17 

.20 

.20 

.25 

.30 

.33 

.42 

LABELS,  GUMMED,  perforated,  in  rolls,  1000  labels  in  a  roll.  Numbers  given  are  same  sizes  as  above. 
Each  roll  contained  in  a  special  box  with  slot  opening  so  that  labels  can  be  drawn  out  as  needed 
without  opening  the  box.  abed 

Trade  No.  ,  205  209  217  221 

Per  Roll  $0.80  .75  .65  .60 

LABELS,  CHEMICAL,  in  book,  names  and  symbols  for  all  chemicals  and  reagents  in  general  use  in 
laboratories.  Gummed  and  perforated  so  that  any  label  may  be  removed  without  destroying  the 

book . Per  Book 

LABELS,  MICROSCOPIC  SLIDE,  34  X  34  inch,  gummed  .  Per  Box 

LABELS,  MICROSCOPIC  SLIDE,  34  X  34  inch,  gummed,  black  border .  Per  Box 

LACTOMETERS.  See  MILK  TESTING  APPARATUS,  Page  468. 

LADLE,  COPPER  with  wood  handle.  Diameter  of  bowl  134  inches,  depth  134  inches,  extreme  length 

8  inches . . 

LAMPS,  ALCOHOL,  of  colorless  glass,  with  ground  glass  cap,  wick  and  wick  holder. 

a  b 

Capacity,  ounces  4  8 

Each  $0.25  .40 

LAMP  WICKS  for  above  glass  Alcohol  Lamps . Per  Dozen 

LAMP,  POLISHED  BRASS,  ALCOHOL,  nickel-plated.  Capacity  2  ounces . 

LAMP  WICKS,  special  for  above . Per  Dozen 

LAMPS,  BLAST.  See  pages  201  and  202. 

LEAD  DISHES.  See  DISHES,  LEAD,  Page  432. 

LITMUS  PAPER,  red,  in  sheets . Per  Sheet  .04.  Per  Quire 

LITMUS  PAPER,  red,  in  books  of  strips . Per  Book 

LITMUS  PAPER,  blue,  in  sheets . Per  Sheet  .04.  Per  Quire 

LITMUS  PAPER,  blue,  in  books  of  strips . .  Per  Book 

LITMUS  PENCIL . 

LOGARITHM  TABLES,  a  heavy  board  card,  1434  X  934  inches,  with  four  place  tables  of  logariths 
and  anti-logariths,  with  table  of  atomic  weights,  also  Factors  for  Analysis.  Computed  by  Dr. 
Hubert  G.  Shaw.  This  card  is  of  convenient  size  for  students’  use  in  the  laboratory.  Used  ex¬ 
tensively  and  for  years  at  the  Massachusetts  Institute  of  Technology . Each 


$0.45 

.10 

.10 


.50 


.18 

.65 

.18 


.66 

.06 

.66 

.06 

.26 


.35 


MAGNIFIERS 

Our  line  of  magnifiers  has  been  selected  with  the  greatest  care.  We  list  below  types  that  have  succeeded  best 
in  meeting  the  diversified  requirements  of  science  laboratories  and  feel,  therefore,  that  our  customers  will  be  able 
to  select  the  type  or  types  best  suited  to  their  particular  needs. 


No.  6816 


No.  6820 


No.  6823 


No.  6825 


No.  74-236 


6815  MAGNIFIER,  TRIPOD,  giving  a  large  clear  field  and  a  magnification  sufficient  for  elementary  work. 

The  lens  may  be  focussed  by  screwing  it  up  and  down  in  its  frame . $0.66 

6817  MAGNIFIER,  POCKET,  single,  34  inch  lens,  mounted  and  encased  in  vulcanite .  -40 

6819  ,  single,  same  as  above,  but  lens  1  inch  in  diameter .  -60 

6820  ,  double,  34  and  34  inch  lenses  mounted  and  encased  in  vulcanite .  *68 

6821  ,  double,  J4  and  1  inch  lenses,  mounted  and  encased  in  vulcanite .  -80 

6823  — — ,  triple,  34>  34  and  34  inch  lenses,  mounted  and  encased  in  vulcanite . _ .  *95 

6826  MAGNIFIER,  CODDINGTON,  sharp  definition,  large,  clear,  flat  field.  Mounted  in  nickel-plated 


74-236  MAGNIFIER,  FOLDING  (LINEN  TESTER),  brass  mounted,  short  focus,  34  inch  aperture  .  .  .  .  .44 

74-230  MAGNIFIER,  READING  (Reading  Lens),  diameter  3  inches,  in  nickel-plated  brass  mount,  polished 

wood  handle  .  1*30 


CHEMISTRY  AND  BIOLOGY 


453 


Nos.  5835  to  5839 


Nos.  5841  to  5845 


Nos.  5847  to  5851 


DOUBLET  MAGNIFIERS.  These  magnifiers  are  composed  of  two  separate  plano-convex  lenses,  very  carefully 
and  accurately  ground  and  polished  and  substantially  set  in  their  mounts.  Nos.  5835  to  6839  are  black  lacquered 
and  Nos.  5841  to  5851  are  nickel-plated.  Excellent  definition  and  an  exceptionally  flat  field  with  greatest  focal  length 
are  characteristics  of  these  lenses. 

For  use  on  Dissecting  Stands. 

5835  6X  DOUBLET  MAGNIFIER,  41.6  mm.  (1.6  inches)  focal  distance,  working  distance  22  mm.,  field  22 

mm . . . 

5836  9X  DOUBLET  MAGNIFIER,  27.8  mm.  (1.1  inch)  focal  distance,  working  distance  15  mm.,  field  16 


mm. 


5837  12X  DOUBLET  MAGNIFIER,  20.8  mm.  (0.8  inch)  focal  distance,  working  distance  12  mm.,  field  11 

mm . 

5838  18X  DOUBLET  MAGNIFIER,  13.9  mm.  (0.5  inch)  focal  distance,  working  distance  8  mm.,  field  8 

mm . ' . 

6839  24X  DOUBLET  MAGNIFIER,  10.4  mm.  (0.4  inch)  focal  distance,  working  distance  6  mm.,  field  5.5 

mm . 

With  Hexagonal  Handles  for  use  on  the  Desk. 

6841  6X  DOUBLET  MAGNIFIER,  41.6  mm.  (1.6  inches)  focal  distance,  working  distance  22  mm.,  field  22 
mm . — . 

5842  9X  DOUBLET  MAGNIFIER,  27.8  mm.  (1.1  inches)  focal  distance,  working  distance  15  mm.,  field  16 

mm . 

5843  12X  DOUBLET  MAGNIFIER,  20.8  mm.  (0.8  inch)  focal  distance,  working  distance  12  mm.,  field  11 

mm . 

6844  18X  DOUBLET  MAGNIFIER,  13.9  mm.  (0.5  inch)  focal  distance,  working  distance  8  mm.,  field  8 


mm. 


6845  24X  DOUBLET  MAGNIFIER,  10.4  mm.  (0.4  inch)  focal  distance,  working  distance  6  mm.,  field  5.5 

mm . . 

In  Folding  Pocket  Cases. 

6847  6X  DOUBLET  MAGNIFIER,  41.6  mm.  (1.6  inches)  focal  distance,  working  distance  22  mm.,  field  22 
mm . 

5848  9X  DOUBLET  MAGNIFIER,  27.8  mm.  (1.1  inches)  focal  distance,  working  distance  15  mm.,  field  16 

mm . . 

5849  12X  DOUBLET  MAGNIFIER,  20.8  mm.  (0.8  inch)  focal  distance,  working  distance  12  mm.,  field  11 

mm . 

5850  18X  DOUBLET  MAGNIFIER,  13.9  mm.  (0.5  inch)  focal  distance,  working  distance  8  mm.,  field  8 

mm . 

6851  24X  DOUBLET  MAGNIFIER,  10.4  mm.  (0.4  inch)  focal  distance,  working  distance  6  mm.,  field  5.5 
mm . 


$1.00 

1.00 

1.00 

1.25 

1.50 

1.00 

1.00 

1.00 

1.25 

1.60 

1.25 

1.25 

1.25 

1.50 

1.50 


MANIKINS 


The  manikin  is  a  reproduction  of  the  Complete  Anatomy  of  the  human  body  in  all  its  details,  and  is  an  invalua¬ 
ble  aid  in  teaching  Physiology. 

It  can  be  hung  upon  the  wall  closed,  occupying  the  space  of  a  picture.  Open  it  and  you  will  see  fold  after  fold 
that  can  be  turned  just  as  you  would  turn  the  pages  of  a  book.  Each  fold  is  a  picture  of  some  part  of  the  Complex 
Anatomy. 

Every  muscle,  ligament,  bone,  nerve,  vein,  artery  and  organ  is  seen  in  its  natural  position. 

Every  such  part  is  numbered  and  its  name  and  purpose  is  learned  by  reference  to  the  index  that  accompanies 
the  Manikin. 

The  Pilz  Manikin,  life  size,  shows  every  detail  of  the  human  body  full  size,  thirty  folds  being  necessary  to  ac¬ 
complish  this. 

It  is  of  indestructible  linen-centered  cardboard  and  will  last  a  lifetime. 

Size:  5  feet,  5  inches  high. 

Number  of  Parts.  There  are  455  parts  covering  all  the  Anterior  and  Posterior  Muscles,  Circulation  of  the  Blood, 
Nervous  System,  Skeleton  and  Viscera. 

6856  Male  full  size,  each . $13.60 

6866  Female  full  size,  each . 17.50 

6867  Sexless  full  size,  each . 13.50 

Dr.  Minder’s  Manikins  are  of  smaller  size,  but  contain  all  of  the  essential  features  of  the  above.  They  are  of 

special  interest  to  schools  not  able  to  purchase  the  large  size  editions. 

Size:  Twenty  (20)  inches  tall. 

Number  of  Parts.  Minder’s  Manikins  contain  384  distinct  parts,  covering  the  Muscles,  Circulation  of  the 
Blood,  Nervous  System,  Skeleton  and  Viscera. 

6869  Female,  each . $3.60 

6860  Sexless,  each .  2.76 

A  key  and  descriptive  text  with  all  parts  named  and  numbered  is  furnished. 

In  ordering  be  particular  to  state  which  manikin  is  wanted,  male,  female  or  sexless. 


454 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


COMPOUND  MICROSCOPES 


The  microscopes  listed  as  follows  with  the  exception  of  Nos.  6868  and  6870 
are  the  product  of  the  Spencer  Lens  Company.  The  best  of  material  is  used  and  is 
worked  by  the  best  modern  machinery  in  the  hands  of  men  of  skilled  mechanics, 
carefully  trained,  each  to  his  particular  work. 

The  stands  are  for  the  most  part  in  a  neat  black  finish  which  is  baked  in  at 
a  high  temperature  and  which  is  resistant  to  wear,  to  acid,  to  alcohol,  and  all  the 
common  reagents.  This  effect  is  heightened  by  the  yellow  finish  of  the  smaller 
parts.  This  yellow  finish  is  also  alcohol  and  reagent  proof. 

We  call  particular  attention  to  features  which  are  peculiar  to  these  microscopes. 

Unexcelled  Optics. 

Fine  adjustments  are  automatically  lubricated  and  protected  from  dust. 

All  fine  adjustments  are  so  protected  that  no  harm  can  come  to  them  from 
handling  the  microscope  by  the  arm. 

All  fine  adjustments  cease  to  work  when  the  objective  rests  on  the  cover  glass. 

No  lost  motion  or  lateral  displacement  in  either  type  of  fine  adjustment. 

Unusually  large  stages  on  which  the  vulcanite  stages  are  vulcanized  directly 
to  the  metal  stage. 

Unexcelled  optical  and  mechanical  workmanship  throughout. 

6868  COMPOUND  MICROSCOPE,  SMALL.  This  microscope,  though 
but  7  inches  high,  is  an  efficient  compound  microscope  for  the  general 
work  of  a  school  laboratory.  Constructed  of  brass  throughout  and 
handsomely  finished.  Stage  is  large  and  provided  with  nickel-plated 
spring  clips.  Furnished  with  ocular  and  three  objectives  giving 
magnifications  of  30,  50,  and  80  diameters.  In  box  with  receptacle 
for  slides  and  forceps  . $9.80 


No.  6870  5870  COMPOUND  MICROSCOPE,  a  low  priced  instrument  of  exception¬ 

ally  fine  quality  well  adapted  for  school  laboratories.  It  is  a  full 
size  instrument  conforming  to  standards  by  Royal  Microscopical  Society,  and  objectives  and  ocu¬ 
lars  of  any  other  make  conforming  to  the  same  standards,  may  be  added  to  its  equipment. 

Stage,  2 %  X  2%  inches,  has  attached  to  it  a  supplementary  micrometer  stage  affording  a  very  deli¬ 
cate  fine  adjustment  with  nickel-plated  spring  stage  clips. 

Stand  is  made  entirely  of  brass,  handsomely  finished  in  lacquer  and  black  enamel.  The  draw  tube 
is  160  mm.  long  and  is  nickel-plated  and  polished  where  it  slides  in  the  main  tube. 

Mirror  is  plane,  1%  inches  diameter,  so  mouthed  that  it  can  be  adjusted  to  any  angle.  With  a  7X 

ocular  and  a  %  and  1  inch  divisible  objective,  in  case  .  . . 13.60 


COMPOUND  MICROSCOPES,  suggested  for  commercial,  house¬ 
hold  or  elementary  school  purposes  where  the  magnification  re¬ 
quired  is  not  great. 

Focussing  adjustment,  coarse  adjustment  only,  by  rack  and 
pinion. 

Stage  of  brass,  black  lacquered.  Measures  112  X  108  mm.  and 
distance  of  optical  axis  to  base  of  arm  is  75  mm. 

Mirror,  plano-concave,  50  mm.  diameter,  on  swing  bar. 


6873  - ,  with  divisible  objective  32-14  mm.  and  10X  ocular  giving 

magnifications  of  35  and  130  diameters . $17.60 

6873A  - ,  with  divisible  objective  32-14  mm.  and  6  mm.  special  ob¬ 

jective  and  6X  and  10X  oculars  giving  magnifications  of  17, 

35,  65, 130  and  360  diameters . 23.00 

6873B - ,  same  as  above,  but  with  revolving  dust-proof  double  nose- 

piece  . 27.00 

6873C  - ,  with  16  and  4  mm.  objectives  and  10X  ocular  giving  mag¬ 
nifications  of  100  and  440  diameters . 26.60 

6873D  - ,  same  as  above,  but  with  revolving  dust-proof  double  nose- 

piece  .  29.60 


No.  6873 


CHEMISTRY  AND  BIOLOGY 


455 


Nos.  5876  to  5876E 


Nos.  5878  to  6878E 


Nos.  6880  to  5880F 


5876 
5876 A 
5876B 

5876C 

6876D 

5876E 


MICROSCOPES,  side  fine  adjustment.  Stage  108  mm.  deep  X  112  mm.  wide,  with  iris  diaphragm  in 
the  stage. 

Plano-concave  mirror  50  mm.  diameter.  Coarse  and  fine  adjustments.  The  fine  adjustment  located 
on  the  side  is  of  simplest  possible  construction  and  cannot  get  out  of  order.  One  complete  revolution 
of  shaft  raises  or  lowers  the  body  tube  .2  millimeter. 

- ,  with  16  and  4  mm.  objectives  and  10X  ocular  giving  magnifications  of  100  and  440  diameters  .  $30.00 

- ,  same  as  above,  but  writh  revolving  dust-proof  double  nosepiece . 34.00 

- ,  with  16  and  4  mm.  objectives  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264  and 

440  diameters . . 31.50 

— ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 35.60 

— ,  with  Abbe  Condenser  (N.  A.  1.20)  16  and  4  mm.  objectives  and  10X  ocular  giving  magnifica¬ 
tions  of  100  and  440  diameters . 39.50 

— ,  with  Abbe  Condenser  (N.  A.  1.20)  16  and  4  mm.  objectives,  with  revolving  dust-proof  double 
nosepiece,  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264  and  440  diameters 


5878 

6878A 

5878B 

5878C 

5878D 

5878E 


MICROSCOPES,  top  lever  type,  fine  adjustment,  stage  108  mm.  deep  by  112  mm.  wide,  with  iris  dia¬ 
phragm  in  the  stage,  plano-concave  mirror  50  mm.  diameter.  Both  coarse  and  fine  adjustments. 
One  complete  revolution  of  shaft  raises  or  lowers  the  body  tube  .5  millimeter. 

- ,  with  16  and  4  mm.  objectives  and  10X  ocular  giving  magnifications  of  100  and  440  diameters  .  . 

- ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 

-,  with  16  and  4  mm.  objectives  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264  and 


41.00 


27.50 

31.50 


440  diameters . .  .  29.00 

— ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 33.00 

— ,  with  Abbe  Condenser  (N.  A.  1.20)  16  and  4  mm.  objectives,  with  revolving  dust-proof  double 

nosepiece,  and  10X  ocular  giving  magnifications  of  100  and  440  diameters . 37.00 

with  Abbe  Condenser  (N.  A.  1.20),  16  and  4  mm.  objectives,  with  revolving  dust-proof  double 


nosepiece,  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264  and  440  diameters  ....  38.60 

COMPOUND  MICROSCOPES  suggested  to  micro-biologists  who  desire  an  efficient,  yet  comparatively  inex¬ 
pensive  instrument. 

Side  fine  adjustment  of  very  simple  yet  practical  construction.  Cannot  get  out  of  order.  One  complete  revo¬ 
lution  of  shaft  moves  body  tube  2Ao  mm. 

Stage,  vulcanized  top  and  sides,  is  112  mm.  wide  by  108  mm.  deep.  Working  space  80  mm.  from  arm  to  optical  axis. 

Substage.  A  sextuple  screw,  protected  from  dust,  carries  the  substage  arm  up  and  down  on  a  perpendicular 
axis,  around  which  the  arm  is  free  to  revolve  when  at  the  lower  limit  of  the  screw.  When  at  the  lower  limit  the  arm 
may  be  swung  out  of  the  optical  axis,  carrying  with  it  the  small  iris  diaphragm  fastened  to  its  upper  surface,  and  also 
the  condenser  with  its  larger  iris.  The  small  upper  iris  is  automatically  locked  open  when  the  condenser  is  in  place. 

6880  -  .  . - 

5880A  - 
6880B  - 


6880C 

5880D 

5880E 

6880F 


with  16  and  4  mm.  objectives  and  10X  ocular  giving  magnifications  of  100  and  440  diameters  .  $31.60 

— ,  same  as  above  but  with  revolving  dust-proof  double  nosepiece . 36.60 

— ,  with  16  and  4  mm.  objectives  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264  and 

440  diameters . 33.00 

— ,  same  as  above,  with  revolving  dust-proof  double  nosepiece . 37.00 

with  Abbe  Condenser  (N.  A.  1.20),  16  and  4  mm.  objectives  with  revolving  dust-proof  double 


nosepiece,  and  10X  ocular  giving  magnifications  of  100  and  440  diameters . 41.00 

— ,  with  Abbe  Condenser  (N.  A.  1.20),  16  and  4  mm.  objectives,  with  revolving  dust-proof  double 

nosepiece  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264  and  440  diameters . 42.50 

with  Abbe  Condenser  (N.  A.  1.20),  16,  4  and  1.8  mm.  (oil  immersion)  objectives  with  revolving 


dust-proof  triple  nosepiece  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264,  440,  570 
and  950  diameters . . 67.50 


456 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  5882  No.  5886 


COMPOUND  MICROSCOPE  suggested  for  advanced  laboratory  research  work  and  clinical  work  of  the  most 
exacting  character. 

Side  fine  adjustment  having  no  lost  motion  and  no  side  thrust,  automatically  taking  up  for  any  wear  as  it  may 
occur.  Each  of  the  one  hundred  divisions  of  the  graduated  button  represents  a  movement  of  1  micron. 

Stage,  110  X  95  mm.,  is  of  brass,  covered  top  and  edges  with  rubber  vulcanized  directly  to  the  stage  plate. 

Substage.  A  sextuple  screw,  protected  from  dust,  carries  the  substage  arm  up  and  down  on  a  perpendicular 
axis,  around  which  the  arm  is  free  to  revolve  when  at  the  lower  limit  of  the  screw.  When  at  the  lower  limit,  the  arm 
may  be  swung  out  of  the  optical  axis,  carrying  with  it  the  small  iris  diaphragm  fastened  to  its  upper  surface,  and 
also  the  condenser  with  its  larger  iris.  The  small  upper  iris  is  automatically  locked  open  when  the  condenser  is  in 


place. 

5882  - ,  with  Abbe  Condenser  (N.  A.  1.20),  16  and  4  mm.  objectives  and  10X  ocular  giving  magnifica¬ 
tions  of  100  and  440  diameters .  . $54.00 

5882A  - ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 68.00 

6882B  - ,  with  Abbe  Condenser  (N.  A.  1.20),  16  and  4  mm.  objectives  and  6X  and  10X  oculars  giving 

magnifications  of  60,  100,  264  and  440  diameters . . . 55.50 

5882C  —  — ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 69.50 


ing  dust-proof  triple  nosepiece,  and  6X  and  10X  oculars,  giving  magnifications  of  60,  100,  264,  440, 

570  and  950  diameters . '.  .  . . 85.00 


COMPOUND  MICROSCOPE  suggested  to  micro-biologists’  who  demand  a  large  and  very  efficient  instrument 
where  critical  work  is  a  necessity. 

Side  fine  adjustment  having  no  lost  motion  and  no  side  thrust;  automatically  taking  up  for  any  wear  as  it  may 
occur.  Each  of  the  one  hundred  divisions  of  the  graduated  button  represents  a  movement  of  1  micron. 

Revolving  Stage,  120  mm.  in  diameter,  is  covered  with  vulcanite;  axis  of  revolution  is  90  mm.  from  the  arm. 
Provided  with  Mechanical  Stage,  buttons  of  which  are  on  concentric  axes;  lateral  movement  60  mm.,  to-and-fro 
movement  38  mm. 

Sub-stage.  May  be  moved  up  and  down  on  its  bearing  by  rack  and  pinion.  The  iris  diaphragm  beneath  the 
condenser  is  located  on  one  arm,  which  swings  to  the  right  and  on  which  provision  is  made  for  oblique  light,  the  de¬ 
centering  secured  by  rack  and  pinion.  The  condenser  is  of  the  drop  swing  type.  The  upper  iris  diaphragm  is  located 
on  one  arm  which  swings  to  the  left.  The  mirror  is  mounted  on  a  swing  arm  mounted  independent  of  the  stage. 

5885  - ,  with  Abbe  Condenser  (N.  A.  1.40),  16  and  4  mm.  objectives,  and  10X  ocular  giving  magnifications 

of  100  and  440  diameters .  . $110.00 

5885A  - ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 114.00 

6886B  - ,  with  Abbe  Condenser  (N.  A.  1.40),  16  and  4  mm.  objectives  and  6X  and  10X  oculars  giving  mag¬ 
nifications  of  60,  100,  264  and  440  diameters . 111.50 

5885C  - ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . .  115.50 

6886D  - ,  with  Abbe  Condenser  (N.  A.  1.40),  16, 4  and  1.8  mm.  (oil  immersion)  objectives,  with  revolving 

dust-proof  triple  nosepiece,  and  6X  and  10X  oculars  giving  magnifications  of  60,  100,  264,  440,  570 

and  950  diameters . 140.00 


CHEMISTRY  AND  BIOLOGY 


457 


BINOCULAR  MICROSCOPES,  offered  to  meet  the  demands  for  a  binocular  instrument  with  wide  range  of 
adaptability. 

Special  Features: — Inclination  Joint.  Long  Range.  The  inclination  part  carries  a  long  slide  which,  when  the 
microscope  is  erect,  projects  downward  through  the  pillar  and  base  until  it  nearly  touches  the  table.  Removable 
Stage.  Universal  Mirror  Adjustment.  Swings  backward,  forward  and  sidewise.  Can  be  used  horizontally  to  ex¬ 
amine  vertical  objects.  Accommodation  for  any  pupillary  distance.  The  light  to  either  eye  can  be  shut  off  by 
a  shutter  which  automatically  returns  to  central  position.  Accurately  paired  objectives  and  oculars. 


6890  ,  with  40  mm.  paired  objectives  and  10X  paired  oculars . $62.00 

6890A  - ,  with  48  and  32  mm.  paired  objectives  and  6X  and  10X  oculars . 77.00 

5890B  - ,  with  66,  40  and  26  mm.  paired  objectives  and  4X,  6X  and  10X  oculars . 92.00 

6890C  - ,  with  66,  48, 32  and  26  mm.  paired  objectives  and  4X,  6X  and  10X  oculars . 104.00 

6890D  - ,  with  66,  48, 40,  32  and  26  mm.  paired  objectives  and  4X,  6X  and  10X  oculars . 116.00 


METALLURGICAL  MICROSCOPES,  suggested  as  inexpensive  microscopes  for  metallurgical  purposes. 
May  also  be  used  to  advantage  in  Biological  work. 

Arm  and  pillar  are  of  a  shape  to  give  a  working  radius  of  85  mm.  from  optical  axis  to  the  arm.  With  inclina¬ 
tion  joint. 

Top  Fine  Adjustment  of  lever  type,  very  sensitive  and  accurate.  One  complete  revolution  of  the  shaft  moves 
body  tube  millimeter. 

Stage,  120  mm.  in  diameter.  The  center  is  covered  by  a  removable  disc  that  may  be  racked  up  and  down  through 
a  distance  of  45  mm.,  or  may  be  removed  entirely  to  allow  placing  under  the  objective  an  object  larger  than  could 
be  accommodated  otherwise. 

Accessories.  Included  at  prices  below  are  the  Vertical  Illuminator  No.  6971  described  on  page  460  and  the  small 
frame  by  which  metals  may  be  held  with  the  polished  side  upwards. 


6896  ,  with  16  and  4  mm.  objectives  and  10X  ocular . $88.00 

6896A  - ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 92.00 

6896B  - ,  with  16  and  4  mm.  objectives  and  6X  and  10X  oculars . 89.60 

6895C  - ,  same  as  above,  but  with  revolving  dust-proof  double  nosepiece . 93.60 

6896D  - ,  with  32,  16  and  4  mm.  objectives,  with  revolving  dust-proof  triple  nosepiece,  and  6X  and  10X 

oculars . . . . 98.00 


6906  DISSECTING  MICROSCOPE,  Regent’s  Type,  complete  with  lens 


1.96 


DISSECTING  MICROSCOPE,  BLOCK,  with  hollow 
center  designed  as  a  receptacle  for  dissecting  tools  and 
magnifiers.  This  is  closed  by  a  door  hinged  at  the  lower 
end.  Heavy  glass  stage  with  a  black  and  a  white  back¬ 
ground  for  use  beneath  the  stage. 

6907  - ,  .with  9X  Doublet  Magnifier  giving  a 

magnification  of  9  diameters,  equivalent 
focus  27.8  mm.,  working  distance  15  mm.  $2.60 

6908  - ,  with  6X  and  12X  Doublet  Magnifiers 

giving  magnifications  of  6  and  12  diam¬ 
eters,  equivalent  foci  41.6  and  20.8  mm. 
and  working  distances  of  22  and  12  mm. 
respectively . .  .  3.26 


No.  6907  Back  View 


458 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


Nos.  5910  to  5910E 


DISSECTING  MICROSCOPE,  rack  and  pinion  focussing  adjustment,  stage  75  X  100  mm.  Covered  by  a  heavy 
polished  glass  plate  with  a  black  and  a  white  background  to  fit  beneath  the  plate.  Metal  hand  rests;  jointed  lens 
carrier  permits  of  use  of  lens  on  any  part  of  the  stage;  plano-concave  mirror  50  mm.  in  diameter.  In  handsome  cabi¬ 
net. 

5910  - ,  with  9X  doublet  magnifier,  magnification  9  diameters.  Equivalent  focus  of  27.8  mm.  and  a 

working  distance  of  15  mm . .  $9.00 

5910A  - ,  with  6X  and  12X  doublet  magnifiers,  magnifications  of  6  and  12  diameters.  Equivalent  foci  of 

41.6  and  20.8  mm.  respectively,  and  working  distance  of  22  and  12  mm.  respectively .  9.75 

5910B  - ,  with  9X  Triple  Aplanat  Magnifier,  magnification  9  diameters.  Large  flat  field  and  great  working 

distance,  equivalent  focus  27.8  mm.,  working  distance  24.5  mm . 11.75 

5910C  - ,  with  6X  and  12X  Triple  Aplanat  Magnifiers  having  magnifications  of  6  and  12  diameters.  Large 

flat  fields  and  great  working  distances.  Equivalent  foci  41.6  and  20.8  mm.  and  working  distances  of 

36.8  and  18.4  mm.  respectively . 15.25 

5910D  - ,  with  9X  Veraplanat  Magnifier,  giving  magnification  of  9  diameters.  Most  critical  definition, 

large,  clear  and  flat  field  and  long  working  distance . 14.25 

5910E  - ,  with  6X  and  12X  Veraplanat  Magnifiers,  giving  magnifications  of  6  and  12  diameters.  Most 

critical  definitions,  large,  clear  and  flat  fields  and  long  working  distances . 20.25 

Note. — Following  outfits  do  not  include  the  metal  hand  rests  illustrated. 

METAL  HAND  RESTS,  extra  .  .  .  .  ‘ . Per  Pair  .75 


DISSECTING  MICROSCOPES,  similar  to  above,  but  focussing  is  accomplished  by  means  of  the  button  at  the 
side  of  the  pillar. 

5912 
5912A 
.  5912B 


5912C 


ACHROMATIC  OBJECTIVES.  These  objectives  are  all  corrected  for  a  tube  length  of  160  mm.  and  for  a  cover 
glass  thickness  of  0.18  mm.  They  give  a  sharp  critical  definition  to  the  edge  of  the  field  and  at  the  same  time  give 
exceptional  long  working  distance  and  unusual  flatness  of  field.  All  objectives  are  made  with  the  Society  Screw 
furnished  by  the  Royal  Microscopical  Society  and  are  interchangeable  with  those  of  European  manufacture.  All 
objectives  are  mounted  directly  into  the  model  and  are  thus  unharmed  when  cleaned  with  a  solvent. 


- ,  with  9X  doublet  magnifier  giving  a  magnification  of  9  diameters,  equivalent  focus  27.8  mm., 

working  distance  15  mm . . . $6.75 

- ,  with  6X  and  12X  Doublet  Magnifiers,  giving  magnifications  of  6  and  12  diameters,  equivalent 

foci  41.6  and  20.8  and  working  distances  22  and  12  mm.  respectively .  7.60 

- ,  with  9X  Triple  Aplanat  Magnifier,  giving  magnification  of  9  diameters.  Large  flat  field  and  long 

working  distance,  equivalent  focus  27.8  mm.,  working  distance  24.5  mm .  9.60 

- ,  with  6X  and  12X  Triple  Aplanat  Magnifiers,  giving  magnifications  of  6  and  12  diameters;  ex¬ 
ceptionally  sharp  definitions,  large,  clear  and  flat  fields  and  long  working  distances.  Equivalent  foci 

41.6  and  20.8  mm.,  working  distances  36.8  and  18.4  mm.  respectively . 13.00 

Note. — The  prices  above  do  not  include  the  Metal  Hand  Rests  illustrated. 

METAL  HAND  RESTS,  extra . Pel-  Pair  .75 


i ITT  V  iiirnr'  itfliMatf '-'~HT  ~  •*<•*•*«■ 


CHEMISTRY  AND  BIOLOGY 


459 


ACHROMATIC  OBJECTIVES 


Catalogue 

No. 

Equivalent 

Focus 

Num. 

Working 

Distance* 

Diam.  of 
the  t  real 
--field 

Price 

mm. 

inches 
approx . 

Aperture 

With  160  mm.  tube  length 
and  lOx  eye  piece 
mm .  mm . 

Fixed 

Mount. 

Adjust. 

Mount. 

5920 

48 

2 

0.10  # 

28.0 

6.5 

$  4.00 

5921 

40 

W 

0.10 

28.0 

6.3 

4.00 

5922 

32 

1  Vs 

0.10 

15.0 

4.7 

4.00 

6924 

6926 

30-22 

variable 

25 

m 

to 

%0 

1 

0.25 

25.0 

2.0 

9.5 

15.0 

8.0 

3.3 

5.00 

$20.00 

6926 

16 

% 

0.25 

5.0 

2.1 

5.00 

5927 

12 

y2 

0.40 

1.8 

1.4 

8.00 

5928 

8 

% 

0.50 

1.5 

1.0 

8.00 

5929 

5 

% 

0.70 

0.4 

0.55 

8.00 

6930 

4 

Ye 

0.85 

0.46 

0.40 

8.00 

18.00 

5931 

3 

y8 

0.85 

0.26 

0.30 

8.00 

18.00 

6932 

Water 

Im. 

Ya 

1.15 

0.22 

0.30 

20.00 

24.00 

6933 

Oil-Im. 

1.8 

Yu 

1.30 

0.13 

0.20 

27.00 

6934 

Oil-Im. 

1.5 

Me 

1.30 

0.10 

0.14 

40.00 

♦Working  distance  is  the  distance  between  the  front  lens  and  cover  glass. 

fReal  field  is  the  distance  of  the  circular  area  seen  through  the  microscope  and  measured  in  the  plane  of  the  object. 
HUYGHENIAN  OCULARS.  These  oculars  all  fit  the  standard  tube  adopted  by  Royal  Microscope  Society  and 
are  interchangeable  with  those  of  European  manufacture.  The  terms  4X,  6X,  8X,  10X,  etc.,  designate  the  mag¬ 
nification  based  on  the  size  of  the  image  projected  the  distance  of  distinct  vision,  i.  e.,  250  mm.  (10  inches). 


5940 

6941 

5942 

5943 
6944 
5946 


— ,  4X  OCULAR,  equivalent  focus,  62.5  mm.  —  2  inches . $1.50 

— ,  6X  OCULAR,  equivalent  focus,  50  mm.  —  2  inches . 1-50 

— ,  6X  OCULAR,  equivalent  focus,  40  mm.  —  1%  inches .  1-50 

— ,  8X  OCULAR,  equivalent  focus,  30  mm. —  1%  inches .  1-50 

— ,  10X  OCULAR,  equivalent  focus,  25  mm.  —  1  inch .  1-60 

— ,  12X  OCULAR,  equivalent  focus,  20  mm.  —  %  inch .  1-50 

REVOLVING  DUST-PROOF  NOSEPIECE,  most  carefully  made  and  greatest  care  exercised  to  see  that  they 
are  perfectly  centered  and  are  strong  enough  to  remain  so.  Neatly  finished  in  alcohol-proof  enamel,  with  the  focal 
lengths  of  the  objectives  used  neatly  engraved  on  the  edge  of  the  revolving  portion. 

6962  REVOLVING  DUST-PROOF  NOSEPIECE,  double . $4.00 

6963  - ,  triple  .' . .  5.50 

6964  - ,  quadruple . . . . 

SUBSTAGE  ABBE  CONDENSERS.  These  are  non-achromatic  lenses  mounted  with  an  iris  diaphragm  beneath 

to  modify  the  amount  of  light  and  with  a  ring  beneath  the  iris  to  hold  a  blue  glass  for  cutting  out  the  yellow  rays 
of  artificial  light. 

5960  ABBE  CONDENSER,  N.  A.  1.20 . $™0 

6961  ABBE  CONDENSER,  N.  A.  1.40  .  9  00 


460 


L.  E.  KNOTT  APPARATUS  CO., 


BOSTON 


MICROSCOPE  ACCESSORIES 


6965  BULL’S  EYE  CONDENSER,  for  illuminating  opaque  objects,  etc. 

A  plano-convex  lens  mounted  on  an  adjustable  stand. 

Diameter  of  lens  inches . . $4.76 

6966  - ,  diameter  of  lens,  3  inches .  6.00 

6968  ABBE  CAMERA  LUCIDA,  showing  the  whole  of  the  field,  the  object  and  the  pencil  point  clearly. 

Prism  so  mounted  that  the  opening  in  the  silvering  case  can  be  lowered  in  the  case  of  the  higher 
power  oculars  or  raised  with  the  lower  powers  until  it  comes  in  the  exact  focus  of  the  ocular.  It  can 
be  so  centered  with  one  hand  by  two  concentric  screws,  that  the  field  is  free  from  color  to  the  ex¬ 
treme  edge.  The  smoked  glasses  are  so  mounted  around  and  below  the  prism  that  the  light  from 
the  pencil  and  the  object  can  be  easily  modified  to  make  them  equally  distinct.  The  mirror  (70  mm. 

X  105  mm.)  is  supported  on  an  adjustable  graduated  bar.  In  mahogany  case . 20.00 

5969  ABBE  CAMERA  LUCIDA,  similar  to  above,  but  the  prism  is  permanently  centered  and  there  is  no 

means  of  modifying  the  light  from  the  ocular . 10.00 


VERTICAL  ILLUMINATORS.  These  instruments  are  constructed  to  screw  into  the  nosepiece,  be¬ 
tween  it  and  the  objective.  The  light  is  directed  into  the  opening  in  the  side  until  it  strikes  the  sil¬ 
vered  surface  from  which  it  is  reflected  down  through  the  objective  to  the  object  to  be  examined.  It 
is  then  reflected  back  through  the  objective  to  the  eye.  The  opening  in  the  side  is  so  arranged  that 
it  can  be  turned  in  any  direction. 

6971  - ,  with  silvered  prism  for  reflecting  the  light.  Prism  is  so  mounted  that  it  can  be  turned  to  reflect 

the  light  down  through  the  objective  as  desired  . .  6.60 

6972  - ,  with  silvered  cover  glass  for  reflecting  the  light.  Provided  with  three  openings  of  different  sizes  .  6.60 

5976  MECHANICAL  STAGE,  new  construction,  so  made  that  the  vernier  reading  designating  the  locations 
of  objects  taken  on  one  microscope  will  register  with  the  readings  for  the  same  objects  taken  on  any 
other  microscope.  This  feature  is  made  possible  from  the  fact  that  the  vernier  for  the  vertical  move¬ 
ment  and  the  arms  holding  the  slide  are  adjustable.  The  stage  will  handle  a  slide  3X2  inches. 

Range  85  mm.  lateral  motion  and  65  mm.  vertical.  In  mahogany  case . 18.00 

6980  MICROSCOPE  LAMP  designed  primarily  for  use  with  the  dark  field  illuminator  and  vertical  illumina¬ 
tor.  This  lamp  serves  most  admirably  as  a  lamp  for  general  microscopic  illumination.  It  works 
on  any  incandescent  circuit,  but  must  always  be  provided  with  a  rheostat  suitable  for  the  voltage. 
Adjustments  provided  for  moving  the  carbons  and  focussing  the  condenser,  also  for  raising  or  lower¬ 
ing  the  height  and  angle  of  the  lamp  on  its  upright  support.  Provided  with  one  blue*and  one  ground 
glass  plate,  both  of  which  fit  into  a  groove  in  front  of  the  condenser.  Complete  with  five  feet  of  Con¬ 
necting  Cord . .  14.00 

6980A  FIXED  RHEOSTAT  for  110  volts — 5  amperes . .  6.60 

6980B  - ,  for  220  volts — 5  amperes . . .  9.00 

6980C  CARBONS  for  use  in  above  lamp  ....  . Each  .06 


CHEMISTRY  AND  BIOLOGY 


461 


MICROSCOPIC  SLIDES  AND  ACCESSORIES 


Ko-  6000  COVER  GLASSES 

We  have  long  been  headquarters  for  the  greatest  variety  of  cover  glasses,  round,  square  or  rectangular.  Our 
stock,  despite  the  shortage  due  to  unusual  conditions,  is  quite  complete.  We  carry  two  thicknesses  in  stock,  —  No.  1 
that  varies  from  0.11  to  0.17  millimeter  thick,  and  No.  2,  from  0.17  to  0.25  millimeter.  Specify  not  only  by  catalogue 
number,  but  give  also  shape,  thickness  number,  size  and  quantity. 


CIRCULAR  COVER  GLASSES 


Thickness  No.  Diameter  Per  Fifty 


5985A 

1 

15  mm.  (^-inch) 

$0.30 

6986B 

2 

15  mm.  (5^-inch) 

.30 

5985 C 

1 

12  mm.  (J^-inch) 

.20 

5985D 

2 

12  mm.  (J^-inch) 

.20 

5986  COVER 

GLASSES, 

CIRCULAR,  18  mm.  (%-inch) 

diameter  .  . 

Per  V2  ounce  $1.00 


RECTANGULAR  COVER  GLASSES 


5988A 

Thickness  No. 

1 

Dimensions 

15  X  15  mm. 

Per  Fifty 

$0.30 

5988B 

1 

12  X  12  mm. 

.20 

5988C 

2 

12  X  12  mm. 

.20 

5988D 

2 

10  X  10  mm. 

.18 

5988E 

1 

32  X  32  mm. 

1.00 

6988F 

1 

35  X  35  mm. 

1.35 

5988G 

1 

22  X  40  mm. 

1.30 

6988H 

2 

22  X  40  mm. 

1.30 

69881 

1 

15  X  45  mm. 

1.10 

6988 J 

2 

15  X  45  mm. 

1.10 

5988K 

1 

36  X  50  mm. 

2.50 

5989  COVER  GLASSES,  SQUARE,  18  X  18  mm.  {%  X  %-inch)  . Per  14  Ounce 

5990  SLIDES,  MICROSCOPIC,  GLASS,  3X1  inch,  ground  edges . Per  Gross 

5992  SLIDES,  GLASS,  concave  centers . Per  Dozen 


6995  LIFE  SLIDE,  HOLMAN’S,  a  deep  cylindrical  cavity  connected  by  a  small  channel  with  a  more  shallow 

beveled  cavity.  Complete  with  cover . 

6000  SLIDE  BOX  AND  COVER,  GLASS,  for  use  in  staining  sections.  Width  2%  inches,  length  3%  inches 

STAINING  JAR.  See  JARS,  Page  461. 

6006  TURN  TABLE,  finely  centered,  all  adjustments  for  preparing  microscope  slides . 

6010  SLIDE  BOX,  of  white  wood,  with  closely  fitting  cover,  grooved,  to  hold  25  slides,  numbered  and  indexed 

6012  SLIDE  BOX  for  100  slides.  Covered  with  a  heavy  cloth.  Hinged  cover  with  two  catches . 

6013  SLIDE  BOX,  similar  to  above,  but  for  30  slides . 

6014  SLIDE  CABINET,  MINOT’S  METAL,  a  most  compact  fire-proof  receptacle  for  storing  slides.  Con¬ 

structed  of  metal  throughout,  neatly  finished,  inside  and  outside,  w'ith  japan.  Contains  30  japanned 
metal  trays,  each  having  a  capacity  for  24  slides.  Each  tray  with  knob  and  card  holder.  The  cabinet 
is  provided  with  brass  lock.  Size  36.5  cm.  high,  32.5  cm.  deep  and  17.5  cm.  wide,  outside  measure¬ 
ments. 

Complete  with  30  trays  . . 


$1.00 

1.68 

1.20 

1.35 

.20 


2.50 

.10 

.40 

.35 


20.03 


462 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


SLIDES,  PREPARED  MICROSCOPE  MOUNTS 


ZOOLOGY 

6020  Knott’s  Prepared  Microscope  Mounts  for  Zoology: 


a  Skeleton  of  Commercial  Sponge .  $0.50 

b  Transverse  section  of  Sponge  Grantia  show¬ 
ing  flesh  and  spicules .  .50 

c  Fresh  Water  Hydra,  entire .  .60 

d  Transverse  section  of  Fresh  Water  Hydra 
Ectodern 
Mesodem 

Endodem . 75 

e  Campanularian  Hydroid  (Obelia) .  .50 

f  Tubularian  Hydroid  (Pennaria) .  .50 

g  Transverse  section  of  Sea  Anemone  (Metrid- 
ium  marginatum)  showing  plan  of  body 

structure  of  coral  polyp...., .  .50 

h  Pedicellaria  of  Echinoderm  (Starfish  or  Sea 

Urchin) .  .50 

i  Amoeba .  1.00 

j  Transverse  section  of  Earthworm .  .50 

k  Circumcesophageal  nerve  ring  and  part  of 

ventral  nerve-cord  of  Earthworm .  1 .00 

1  Transverse  section  through  heart  of  Clam...  .50 

m  Transverse  section  through  gill  of  Clam....  .60 

n  Mouth  parts  of  biting  Insect:  Labrum,  Man¬ 
dibles,  Maxillae.  Maxillary  palpi.  Labium, 

and  Labial  palpi .  .70 

o  Proboscis  of  House  Fly . 50 

p  Wing  of  Fly .  .50 

q  Spiracle  of  Cricket .  .50 

r  Tracheae  of  Insect .  .50 

s  Scales  on  Wing  of  Moth .  .50 

t  Section  through  Compound  Eye .  £5 

u  Gizzard  of  Cricket .  .50 

v  Mouth  Parts  of  Honey  Bee .  .65 

w  Blood  of  Fish . 55 

x  Blood  of  Frog . .55 

6021  Price,  complete  set,  as  listed  above .  12.00 


PHYSIOLOGY 

6023  Knott’s  Prepared  Microscope  Mounts  for  Physiology: 

a  Blood,  Human .  $0.70 

b  Blood,  Frog,  double  stained .  .55 

c  Bone,  longitudinal  section,  showing  Haver¬ 
sian  canals,  canaliculi  and  lacunae .  ,80 

d  Bone,  transverse  section,  showing  Haversian 

systems,  etc .  .80 

e  Cerebrum,  section  showing  white  and  gray 

matter,  etc .  .50 

f  Cerebellum,  showing 

1  Cortical  layer  of  gray  matter. 

2  White  matter  of  medulla,  white  me¬ 
dullary  substance,  the  granule  layer, 
the  molecular  stratum,  and  the  layer 

of  the  cells  of  Purkinji .  .50 

g  Stomach,  transverse  section,  showing  the 

general  arrangement  of  its  coats 

1  Mucosa  containing  tubular  peptic 
glands  and  acid  cells. 

2  Sub-mucous  coat. 

3  Blood  vessels. 

4  Circular  and  longitudinal  muscular 
layers. 

5  Fibrous  tunic  covered  with  peri¬ 


toneum .  .50 

h  Small  intestine,  transverse  section,  showing 

villi,  unicellular  glands,  mucosa,  etc .  ,80 

i  Section  of  Spleen .  .60 

j  Adipose  tissue .  .50 

k  Connective  tissue . 50 

1  Heart  muscle,  double  stained,  showing  cross 
striations,  nuclei,  and  characteristic  branch¬ 
ing  of  cardiac  muscle  cells .  .50 

m  Voluntary  muscles,  double  stained,  showing 

cross  striations,  nuclei  saicolemma,  etc.  .50 

n  Involuntary  muscle,  teased  preparation,  show¬ 
ing  isolated  muscle  cells  with  nuclei .  .60 

o  Nerve  Cells,  from  Cerebrum,  showing  pro¬ 
toplasmic  processes  and  nuclei .  .50 


p  Cartilage,  hyaline .  $0.50 

q  Spinal  Cord,  transverse  section .  .50 

r  Large  Intestine,  double  stained .  .55 

s  Sciatic  Nerve,  transverse  section  showing 
axis-cylinder,  medullary  substance,  sup¬ 
porting  connective  tissue,  etc .  .50 

t  Scalp,  section  of.  showing  hair,  follicles,  and 

sebaceous  glands .  .70 

u  Skin,  section  of,  showing  sweat  glands .  .70 

v  Lung,  section  of.. . 50 

w  Liver,  section  of,  with  blood  vessels  injected 

with  red  gelatin . 55 

x  Kidney,  section  of,  injected .  .55 

y  Retina  of  Eye,  showing  coats . 80 

6024  Price,  complete  set,  as  listed  above .  12.00 


BOTANY 

6026  Knott’s  Prepared  Microscope  Mounts  for  Botany: 


a  Longitudinal  section  of  root  tip  of  onion,  show¬ 
ing 

1  Root  Cap. 

2  Cell  division  and  various  icaryokinetic 

nuclear  stages .  $0.65 

b  Longitudinal  section  through  apical  cell  of 

Nitella .  .80 

c  Cell  formation  by  budding .  .50 

d  Spirogyra  showing 

1  Protoplasm  and  nucleus. 

2  Chlorophyll  bands .  .65 

e  Spirogyra  in  conjunction. . . .  .55 

f  Spores  of  Corn  Smut .  .50 

g  Mucor  (black  mould  of  bread) . 50 

h  Section  through  archegonium  of  moss .  .75 

i  Section  through  antheridium  of  moss .  .75 

j  Peristome  of  moss  (Polytricum) .  .50 

k  Prothallium  of  fern  (Polypodium)  showing 

1  Reproductive  organs. 

2  Chlorophyll  bodies . 60 

1  Section  through  archegonium  of  fern  pro¬ 
thallium .  .95 


m  Prothallium  with  young  fern  attached .  .80 

n  Transverse  section  of  rhizome  of  fern  (Pteris) 
showing 

1  Close  1  concentric  fibro-vascular  bun¬ 
dles. 

2  Scalariform  vessels. 

3  Parenchyma. 

4  Parenchymatous  sclerenchyma. 


5  Prosenchymatous  sclerenchyma .  .55 

o  Longitudinal  section  of  n,  showing  1,2,3,  4, 

5,  in  longitudinal  view .  .55 

p  Sporangin  and  Spores  of  Fern . 50 

q  Longitudinal  tangential  section  of  wood  of 

Pine  showing  cut  ends  of  Medullary  Rays  .50 
r  Longitudinal  Radial  section  of  wood  of  Pine 
showing 

1  Pitted  tracheids. 

2  Medullary  rays. . .  .50 

s  Transverse  section  of  vine  stem  showing  first 

year's  growth  and  arrangement  of  fibro- 

vascular  bundles .  .50 

t  Tran  verse  section  of  wood  of  Pine .  .50 

u  Epidermis  of  leaf  showing  stomata .  .50 

v  Transverse  section  of  leaf  of  Trillium .  .50 

w  Transverse  section  of  ovary  of  Trillium..,.  .50 


x  Transverse  section  of  stem  of  Indian  Com 
showing 

1  Conjoint,  collateral,  closed  vascular 
bundles. 

2  Parenchyma. 

3  Sclerenchyma .  .75 

y  Transverse  section  of  exogenous  stem  show¬ 
ing 

1  Cortex. 

2  Camnium . 

3  Rings  of  growth. 

4  Pith. 

5  Medullary  rays .  .50 

6027  Price,  complete  set,  as  listed  above .  12.00 


CHEMISTRY  AND  BIOLOGY 


463 


SPECIAL  MICROSCOPIC  SLIDES 

These  slides  are  very  valuable  as  indicating  a  wider  range  of  structures  than  the  previous  sets.  They  will  be 
found  especially  valuable  to  all  teachers  who  are  using  or  intend  to  use  THE  NATIONAL  BIOLOGY  NOTE-BOOK. 
To  assist  such  teachers  the  numbers  of  the  sheets  in  the  note-book,  in  which  slides  are  particularly  useful,  are  in¬ 
dicated  at  the  right. 


6030  BOTANY. 


a  Spirogyra  in  Conjugation  (B30) . $0.75 

b  Conceptacles  of  Fucus  (F10) . 75 

c  Section  of  Cotyledon  showing  starch  grains  (F20)  .50 

d  Section  of  Wheat  (F21) . 75 

e  Section  of  Oats  (F21) . 75 

f  Section  of  Nut  (F21) . 75 

g  Section  of  Pine  (F21) . 75 

h  Root-tip  of  Barley  (F30) . 65 

i  Root- tip  of  Dandelion  (F30) . 65 

j  Leaf-bud  of  Sycamore  (F40) . 65 

k  Flower-bud  of  Wallflower  (F40) . 65 

1  Flower-bud  of  Lily  (F40) . 65 

m  Section  through  Anther  showing  pollen  chambers 

(low  power)  (F60) . 65 

n  Varieties  of  Stamens  showing  methods  of  dehis¬ 
cence  (low  power)  (F60) .  1 .00 

o  Different  types  of  Pollen  Grains  (low  power) 

(F60) . 65 

p  Cross-section  of  Simple  Ovary  showing  ovules 

(low  power)  (F60) . 65 

q  Sections  of  Compound  Ovary  showing  types  of 

placentae  (low  power)  (F60) .  1 .00 


A  Set  of  Bacteria  Slides  Showing: 
r  1  Diplococcus  (Y20) 
s  2  Staphylococcus  (Y20) 
t  3  Streptococcus  (Y20) 

u  4  Bacillus  (Tetanus  with  spores,  an  excellent 
type  form)  (Y20) 
v  5  Comma  Bacillus  (Y20) 
w  6  Streptobacillus  (Y20) 

x  7  Streptothrix  (Y20) . Complete  set  $7.00 


6033  ZOOLOGY. 

a  Paramoecium  (Rll) .  1.00 

b  Paramoecium  in  Conjugation  (Rll) .  2.50 

c  Carchesium,  double  stained  (Rll) .  2.00 

d  Mitosis  in  Protozoa  (Opalina),  beautiful  slide 
with  two  large  nuclei  in  Mitosis,  triple  stained. 

One  of  the  most  admirable  specimens  for  show¬ 
ing  the  metotic  cell  division  (Rll) .  2.50 

e  Hydra  showing  both  reproductive  organs  (Rll)  2.00 

f  Hydra  showing  ovary  and  bud  (R1 1) .  2.50 

g  Hydra  showing  bud  (Rll) .  2.00 

h  Slides  showing  mitosis  in  Spermary  (Rll) . 2.50 


We  frequently  have  been  requested  to  supply  a  series  of  slides  particularly  adapted  to  the  requirements  of  schools 
which  do  not  differentiate  between  the  biological  sciences.  We  offer,  therefore,  for  those  schools  the  following  lists 
of  slides  selected  as  best  adapted  to  a  general  biology  course  of  Botany,  Physiology  and  Zoology. 


6035 


6036 

6038 


GENERAL  BIOLOGY  COLLECTION,  40  Microscopic  Slides  selected  to  accompany  a  general  course  in 
Botany,  Physiology  and  Zoology. 


I  ALGAE: 

Chlorophyceae  (Green  Algse) 

Conjugates 

a  Spirogyra;  (Conjunction  and  zygo¬ 
spores),  V.  T.  of  glyc . $0.60 

II  FUNGI 

Phycomycetes 

b  Mucor  (or  Rhizopus),  zygospores . 60 

III  MUSCI  (MOSSES) 

c  Funaria,  small  plants  with  rhizoids, 

whole . 50 


IV  FILICALES 

Leptosporanglatse 

d  Pteris,  T.  S.  and  L.  S.  of  the  rhizone. .  .60 

V  GYMNOSPERM/E  (Gymnosperms,  cyads, 


conifers,  etc.) 

Coniferales 

Ptnaceae 

Abietlneae 

e  Pinus,  L.  S.  of  the  staminate  cone . 60 

f  Pinus,  cross  section  of  the  leaf . 50 

g  Pinus,  Ra.,  Ta.,  and  Tr.  sections  of  the 

wood . 60 


VI  ANGIOSPERMS 

Stems 

Monocotyledones 

h  Sea  Mays,  L.  S.  and  T.  S.  general  stem 
structure  with  collat.  bundles . 

Leaves 

Sections  showing  structure 

i  Lilium  pardalinum,  T.  S.  (general 
structure) . 

The  Flower 

Stamens,  anthers,  pollen,  male 
gametophytes 

j  Lilium,  T.  S.  of  anther . 

VII  PROTOZOA 

Rhizopoda 

Lobosa 

k  Amoeba,  1st  class . 

VIII  PORIFERA 

1  Skeleton  of  Commercial  Sponge . 

IX  CCELENTER  AT  A 

Hydrozoa 

Leptolinte 

m  Hydra,  E . 

n  Hj'dra,  T.  S . 


.50 


.50 


.60 


1.00 

.50 


.75 

.60 


,  complete  set  as  listed  above 


X  PLATYHELMINTHES 
Cestoda 

o  Taenia  solium,  proglottis,  E . $0.60 


XI  NEMATHELMINTHES 

Nematoda 

p  Trichinella  spiralis,  in  flesh . 

XII  ECHINODERMATA 

Echinoidea 

q  Echinus,  pedicellaria . 

XIII  ANNULATA 

Chaetopoda 

Oligochaeta 

r  Lumbricus,  earthworm,  T.  S . 

XIV  ARTHROPODA 

Insecta 

Musca  domestlca  (House  Fly) 

s  Insect,  proboscis . 

Lepldoptera 

Bombyx  (Silk  Moth) 

t  Imago,  scales . 

Coleoptera 

Dytiscus  marginalis  (Water  Beetle) 

u  Insect ;  trachea . 

v  Insect;  maxilla  and  palpus . 

XV  CHORDATA 

Mammalia 

Cat  Tissue,  D.  S. 

w  Cerebrum., . 

x  Duodenum,  T.  S . 

y  Eye,  retina . 

z  Heart;  cardiac  muscle,  striations,  etc. 

aa  Liver . 

bb  Lung;  Alveolar  structure,  bronchi,  etc 
cc  Muscle,  voluntary,  T.  S.  and  L.  S. 

dd  Nerve  Cells,  multipolar . 

ee  Nerve  fibers,  medullated  (Sciatic  Nerve) 

ff  Pad  of  Toe . . . 

gg  Stomach,  T.  S.,  Cardiac . 

hh  Trachea,  T.  S . 

Rabbit  Tissues,  D.  S. 

ii  Kidney,  T.  S . 

Ox  Tissues 

jj  Ear;  yellow  elastic  cartilage . 

kk  Ligamentum  nuchae . 

HUMAN  HISTOLOGY 

11  Blood;  leukaemia,  D.  S . 

mm  Scalp:  white . 

an  Skin:  white,  sweat  glands,  etc . 


.60 


.50 


.50 


.50 


.45 


.60 

.60 


.60 

.60 

.60 

.50 

.60 

.50 

.60 

.60 

.60 

.60 

.60 

.50 

.60 

.60 

.60 


.50 

.50 

.50 


$20.00 


SLIDE  MAKING  MATERIAL.  Teachers  of  Biology  oftentimes  have  considerable  difficulty  in  as¬ 
sembling  material  for  mounting  on  slides.  We  have  arranged  for  a  careful  selection  of  50  packages 
of  materials,  diatoms,  pollens,  seed  spores,  parts  of  plants,  insects,  hairs,  etc.,  etc.,  prepared  es¬ 
pecially  for  mounting.  Per  set  of  50  packages  .  . . 


464 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6040 

6040  MICROTOME,  HAND.  The  object  is  placed  in  a  clamp  in  the  upper  end  of  the  tube  and  is  raised 
through  the  hole  in  the  glass  plate  by  an  accurately  cut  screw  which  is  entirely  enclosed  from  dust 
and  injury.  The  feed  is  accurate  and  finely  graduated,  each  division  representing  10  microns.  The 
plate  at  the  top  is  3  inches  in  diameter  and  makes  a  firm  support  for  the  knife . $6.00 

6042  MICROTOME,  TABLE.  Can  be  readily  attached  by  a  screw  clamp  to  the  laboratory  table  or  other 
support.  Object  clamp  sets  in  a  vertically  moving  socket  held  as  illustrated.  Feed  regulated  by 
micrometer  screw  with  graduated  disc  and  index  plate.  Glass  surface  plates  provide  traveling 


ways  which  are  extra  long,  so  that  the  knife  will  not  be  drawn  off  from  the  ends . 12.60 

6043  - ,  same  as  above,  fitted  with  CO2  Freezing  Attachment  No.  6069  .  22.60 

6044  - — — ,  same  as  No.  6042,  fitted  with  Ether  Freezing  Attachment  No.  6067  .  18.50 


MICROTOME,  AUTOMATIC  LABORATORY,  for  attaching  to  the  edge  of  the  table.  The  upper  part  of  the 
casting  of  which  the  table  clamp  is  a  part  is  designed  as  a  frame  which  forms  a  support  for  the  laterally  swinging 
arms  which  carry  the  knife  holder.  By  an  ingenious  method  of  mounting  this  holder,  the  knife  is  given  a  move¬ 
ment  which  utilizes  the  entire  length  of  the  cutting  edge,  thus  insuring  uniform  wear  and  permitting  the  cutting  of 
large  sections.  Absolute  uniformity  of  thickness  in  all  sections  is  insured. 

Feed  secured  by  a  vertical  feed  screw  with  fine  micrometer  thread.  This  feed  screw  is  keyed  to  an  accurately 
cut  ratchet  wheel  in  the  teeth  of  which  a  hardened  steel  pawl  engages.  This  pawl  may  be  thrown  out  or  may  be  set 
to  cut  sections  of  any  desired  thickness.  Each  division  of  the  graduated  scale  marks  5  microns. 

The  drop  pan  beneath  the  object  clamp  may  be  removed  if  desired  and  it  will  be  found  desirable  to  remove  it 
when  the  freezing  chamber  is  attached. 

6046  MICROTOME,  AUTOMATIC  LABORATORY.  Complete  with  one  knife  and  object  clamp  for  par¬ 


affine  or  celloidin.  In  case .  . $45.00 

6047  - ,  same  as  above,  but  fitted  with  COa  Freezing  Attachment.  (See  No.  6069) . .  55.00 

6048  - ,  same  as  No.  6046,  but  fitted  with  Ether  Freezing  Attachment.  (See  No.  6067) .  51.00 

No.  6050 

ROTARY  MICROTOME 

New  Construction 


This  microtome  is  the  result  of  a  most  careful  investigation  of  the  requirements  for  a  rotary  microtome  and  a 
thorough  study  of  the  inaccuracies  inherent  in  the  earlier  types.  There  are,  in  this  new  instrument,  a  number  of 
points  of  advantage  which  will  readily  recommend  themselves  to  the  most  exacting  operator. 

An  accurate  and  reliable  feed  mechanism  acting  entirely  independent  of  any  inaccuracies  due  to  the  up  and 
down  movement  of  the  object. 

A  modified  escapement  in  connection  with  the  ratchet  wheel  insures  against  momentum,  —  a  cause  for  inaccuracy 
in  the  older  models. 

The  feeding  is  done  when  the  object  is  above  the  knife. 

Feed  adjustment  is  convenient  and  definite  and  may  be  set  for  any  thickness  from  1  micron  to  60  microns. 


No.  6042 


No.  6046 


CHEMISTRY  AND  BIOLOGY 


465 


No.  6050 


Total  excursion  of  the  feed  is  37  mm.,  —  double  that  of  most  microtomes. 

The  feed  pawl  is  automatically  raised  above  the  teeth  on  the  return  stroke  and  feeding  is  automatically  stopped 
when  the  feed  nut  has  reached  its  limit. 

The  adjusting  of  the  object  to  the  knife  can  be  done  more  delicately  than  on  any  other  microtome. 

The  object  clamp  is  absolutely  rigid,  of  great  capacity  and  is  most  easily  and  carefully  oriented. 

An  up  and  down  stroke  of  50  mm.  is  possible,  —  sufficient  for  cutting  very  large  sections,  also  for  cutting  celloidin 
sections. 

The  knife  may  be  attached  at  each  end  at  the  edge  as  well  as  at  the  back.  These  clamps  may  be  moved  towards 
one  another  to  provide  additional  rigidity  when  desired  and  to  permit  using  practically  the  whole  of  the  cutting  edge 


of  the  knife  before  resharpening. 

The  whole  mechanism  is  covered  dust-proof. 

The  microtome  may  be  run  by  a  motor. 

With  three  object  discs,  one  knife  and  handle  and  back  for  sharpening,  all  in  case . $100.00 

6060A  KNIFE  HOLDER  for  celloidin  sections . Extra  16.00 

6050B  KNIFE  fox  paraffine  sections . Extra  5.00 


6060C  KNIFE  for  celloidin  sections  Extra  $6.00 

6051  MOTOR  with  enclosed  speed  regula¬ 
tor,  mounted  on  neat  microtome 
table  38  X  26  inches.  For  110 
volts . Extra  60.00 

6062  -  — ,  same  as  above,  for  220  volts 

Extra  60.00 

6053  RIBBON  CARRIER,  an  aluminum 
cylinder,  inches  long  by  25-6 

inches  diameter.  It  is  mounted  in 
an  aluminum  frame  work  under  the 
base  of  which  are  little  rollers  roll¬ 
ing  in  the  direction  of  the  long  di¬ 
mension  of  the  frame.  The  end  of 
the  ribbon  adheres  to  the  cylinder, 
which  in  use  is  slowly  turned  by 
the  buttons  as  the  ribbon  lengthens. 

At  the  same  time  the  cylinder  and 
frame  are  gently  pushed  forward 
on  the  rollers  to  place  the  ribbon  on 
the  cylinder  in  the  long  spiral  .  .  $8.00 


466 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


MICROTOME  ACCESSORIES 


No.  6067 


6067  MICROTOME  FREEZING  ATTACHMENT  FOR  ETHER.  Consists  of  a  freezing  chamber  of  hard 
rubber  which  so  prevents  the  radiation  of  the  cold  that  the  tissue  is  quickly  frozen.  The  ether  is 
held  in  a  metal  tank  which  for  filling  may  be  unscrewed  from  the  support  from  which  it  is  suspended. 

This  attachment  will  freeze  tissue  15  millimeters  in  diameter  and  3  mm.  thick  in  one  minute,  using  only 

5  cubic  centimeters  of  ether . $6.00 

6069  MICROTOME  FREEZING  ATTACHMENT  FOR  CARBON  DIOXIDE,  for  use  on  Microtomes  Nos. 

6042  and  6046.  The  freezing  chamber  is  provided  with  a  pin  like  that  on  the  object  clamp  which 
fits  into  the  same  socket  on  the  microtome.  The  chamber  is  connected  with  the  CO2  chamber  by  a 
flexible  copper  tube.  With  this  freezing  attachment  it  is  possible  to  cut,  stain  and  mount  a  section 
ready  for  examination  in  one  and  one-half  minutes  from  the  time  the  tissue  is  put  in  the  chamber. 
Complete  with  copper  tube  connections . 10.00 


Nos.  6073  to  6081 


No.  6084 


6073 

6074 
6076 

6076 

6077 

6078 

6079 
6081 
6082 
6084 


6086 


6088 


6090 

6092 


MICROTOME  KNIVES.  These  knives  are  broad  and  heavy,  steel  most  carefully  selected,  evenly 
tempered  throughout  their  lengths.  They  are  ground  perfectly  true  so  that  when  one  is  placed  on  an 
absolutely  plane  surface,  the  edge  touches  along  its  whole  length,  while  the  back  does  the  same. 

- ,  50  mm.  cutting  edge . 

- ,  110  mm.  cutting  edge . 

- ,  120  mm.  cutting  edge . 

- ,  185  mm.  cutting  edge . .  ,  . 

- ,  240  mm.  cutting  edge,  Wald  make . , *; 

- ,  250  mm.  cutting  edge . .  , 

- ,  110  mm.  cutting  edge,  ground  especially  for  celloidin . 

- ,  150  mm.  cutting  edge,  with  handle . 

- ,  special  Wald  make,  240  mm.  cutting  edge,  curved  metal  shank . 

MICROTOME  KNIFE  HANDLE  for  holding  the  knives  while  sharpening.  Handles  ebonized,  metal 

parts  finely  nickel-plated . 

MICROTOME  KNIFE  BACKS.  In  order  that  the  knife 


$2 
4 
6 

7 

8 
12 

6 
4.76 
10.26 


1.00 


may  rest  upon  the  honing  stone  at  the  proper  angle 
when  being  sharpened,  a  special  steel  honing  back  has 
been  designed.  This  slips  ever  the  back  of  the  knife  $0.60 
MICROTOME  KNIFE  STROP,  a  flat  piece  of  wood 
with  a  handle  at  one  end.  At  one  side  of  this  strop 
is  cemented  a  piece  of  leather  1%  inches  wide  and  11 
inches  long,  into  which  a  very  fine  carborundum  pow¬ 
der  has  been  rubbed.  The  other  side  is  covered  by  a 

very  fine  grade  of  leather  for  finishing .  .90 

PITH  for  cutting  sections . Per  Package  .10 

WARMING  TABLE  for  use  in  embedding  objects  in 
paraffine.  Copper  plate,  14  X  4  inches  on  stand 

inches  high .  1.60 

PARAFFINE  BATHS.  See  BATHS,  PARAFFINE,  Page  409 


oooo§8§ 


CHEMISTRY  AND  BIOLOGY 


467 


MILK  TESTING  APPARATUS 


No.  6100 


No.  6102 


6100  HAND  DRIVE  TWO-BOTTLE  BABCOCK  MILK  TESTER.  Consists  oi  but  two  castings  forming 

the  gear  case  united  at  a  ground  joint,  forming  an  air-tight  gear  case.  Drive  secured  by  one  large 
steel  gear  and  the  steel  vertical  spindle  which  has  spiral  teeth  directly  milled  into  it. 

Bottle  carriers  of  heavily  tinned  malleable  iron  are  removably  attached  to  the  top  of  the  spindle.  Ro¬ 
tating  pockets  are  seamless  brass. 

Complete  for  milk  testing,  including  test  bottles,  pipette,  acid  measure,  test  bottle  brush,  pint  bottle 
of  acid  and  full  directions  for  making  tests . $4.00 

6101  - ,  with  addition  of  cream  test  bottles,  for  making  both  milk  and  cream  tests .  4.60 


6102  HAND  DRIVE  FOUR-BOTTLE  BABCOCK  MILK  TESTER,  same  as  No.  6100,  but  with  bottle 
carrier  for  four  bottles  and  four  seamless  brass  pockets. 

Complete  with  test  bottles,  pipette,  acid  measure,  test  bottle  brush,  pint  bottle  of  acid,  and  full  di¬ 
rections  .  6.00 


6103 


-,  with  addition  of  cream  test  bottles,  for  making  tests  for  both  milk  and  cream .  6.60 


6106  BABCOCK  TEST  TRAVELING  OUTFIT.  Comprises  No.  6102  Four-Bottle  Babcock  Milk  Tester, 

3  Babcock  Full  Milk  Test  Bottles,  2  Cream  Test  Bottles,  2  Double-neck  Skim  Milk  Bottles, 

1  Pipette,  graduated  for  both  milk  and  cream,  1  Test  Bottle  Brush,  1  Acid  Measure,  1  small 
Quevenne  Lactometer,  1  glass  Thermometer,  1  bottle  Testing  Acid,  all  with  full  directions  for 
making  milk,  cream  and  butter  tests. 

In  hardwood  Carrying  Case  with  separate  compartments  for  glassware  and  acid.  Weight  complete, 

15J4  pounds . . . 10.00 

6107  HAND  DRIVE  ENCLOSED  BABCOCK  MILK  TESTERS  for  6-inch  long  test  bottles.  Bottle  carriers 

are  solid  malleable  iron  castings  heavily  tinned,  swinging  pockets  of  seamless  brass  with  tinned 
malleable  hangers.  Solid  cast  iron  case  is  16  inches  in  diameter;  cover  split 
and  hinged.  Rotation  is  secured  through  a  pair  of  steel  worm  or  spiral  gears 
and  a  pair  of  steel  spur  gears  which  are  mounted  on  a  separate  frame  detach¬ 
ably  secured  to  the  under  side  of  the  body. 

These  machines  turn  with  remarkable  ease  and  run  with  that  smoothness  and 
freedom  from  jar  that  are  required  to  make  an  accurate  test. 

Prices  include  milk  test  bottles,  pipette,  acid  measure,  test  bottle  brush,  pint 
of  acid  and  full  directions,  all  securely  packed. 


No.  of  Bottles 
,  Complete 


a 

6 

$9.00 


b 

8 

10.00 


c 

10 

12.00 


d 

12 

14.00 


No.  6107d 


468 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


Direct  Connected 


Motor-Belt-Driven 

Nos.  6112a-d 


6109 


6110 

6112 


MOTOR  DRIVEN  TWO-BOTTLE  BABCOCK  MILK  TESTER,  for  6-inch  long  test  bottles.  This 

machine  consists  of  a  Yao  H.  P.  vertical  spindle  electric  motor  which  carries  directly  on  the  extended 
spindle,  the  bottle  carriers  with  swinging  pockets. 

Complete  with  regular  equipment  of  glassware  and  sundries  as  ordinarily  supplied.  (When  ordering 

state  whether  for  D.  C.  or  A.  C.  and  voltage.  If  A.  C.,  state  also  the  number  of  cycles  and  phases)  .  $36.00 
MOTOR  DRIVEN  FOUR-BOTTLE  BABCOCK  MILK  TESTER,  same  as  above,  but  with  four  bot¬ 
tle  carriers  and  necessary  extra  glassware  and  sundries . - . 36.00 


MOTOR  DRIVEN  ENCLOSED  BABCOCK  MILK  TESTERS,  direct  connected,  for  6-inch  long  test 
bottles.  In  these  machines  the  motor  has  a  vertical  shaft  on  which  the  bottle  carrier  is  directly 
mounted.  This  brings  the  motor  underneath  the  machine.  In  this  construction  the  weight  of  the 
bottle  carrier  and  its  load  of  bottles  is,  of  course,  directly  on  the  motor.  The  motor  belt  driven  style, 
while  not  so  compact,  will  be  found  the  most  desirable,  all  things  considered. 

When  ordering,  specify  style  desired,  also  whether  for  A.  C.  or  D.  C.  circuits  and  voltage. 


state  number  of  cycles.  a  b 

No.  of  Bottles  6  8 

Complete,  Direct  Connected  Type  or  Motor-Belt  Driven  $49.00  60.00 


If  A.  C., 
c 

10 

62.00 


d 

12 

64.00 


No.  6116  No.  6123  No.  6126  No.  6130  No.  6132  No.  6136  No.  6139  No.  6141*No.  6146  No.  6147  No.  6160 


6116 

6118 

6119 

6120 
6123 
6126 

3803 

6130 


6132 

6134 

6136 

6137 
6139 

6141 

6142 

6143 

6146 

6147 

6150 

6161 

6152 

6155 

6160 


CREAM  TEST  BOTTLES,  6-inch,  9-gram,  30  per  cent.  X  Y  per  cent . Per  Dozen 

CREAM  TEST  BOTTLES,  6-inch,  18-gram,  30  per  cent.  X  Yi  per  cent . Per  Dozen 

- ,  40  per  cent.  X  Y  per  cent . . . Per  Dozen 

- ,  50  per  cent.  X  Yi  per  cent . Per  Dozen 

MILK  TEST  BOTTLES,  6-inch,  18-gram,  10  per  cent.  X  Ye>  per  cent . .  Per  Dozen 

SKIM  MILK  TEST  BOTTLE.  Gives  readings  down  to  one  hundredth,  each  space  representing  five 


TEST  BOTTLE  BRUSH  for  cleaning  Babcock  bottles . 

ACID  BURETTES  in  17.5  cc.  divisions.  abed 

No.  of  Charges  3  6  12  25 

Each  $2.00  2.00  2.50  3.00 

CREAMOMETER  JAR,  12  X  2  inches,  graduated  0-30  and  M  or  PM . 

FUNNEL,  ACID,  for  filling  milk  and  cream  test  bottles  with  acid . 


LACTOMETER,  SPENCE’S,  New  York  Board  of  Health  pattern;  0°  to  120°  by  2°  divisions  .... 
LACTOMETER,  QUEVENNE’S.  Scale  15°  to  40°  by  single  degrees.  Sp.  gr.  Scale  1.015  to  1.040 

ACID  MEASURE,  17.5  cc . 1 . . 

ACID  PIPETTE,  accurately  graduated,  17.6  cc . 

- ,  accurately  graduated,  18  cc . 

- ,  combined  graduated,  with  two  marks,  17.6  and  18  cc . 

AUTOMATIC  PIPETTE.  To  operate,  squeeze  rubber  bulb,  then  insert  point  of  pipette  in  milk,  release 

bulb  and  the  pipette  fills,  the  overflow  going  into  the  large  glass  bulb . 

IMPROVED  PIPETTE.  By  suction  milk  is  drawn  up  until  it  is  above  the  glass  top,  the  stopcock  is 

then  closed  and  the  measured  milk  is  put  in  the  test  bottle . 

BICHROMATE  POTASSIUM  TABLETS  for  preserving  composite  test  samples . Per  50 

CORROSIVE  SUBLIMATE  TABLETS  for  preserving  and  coloring  samples . Per  50 

FARRINGTON’S  ALKALINE  TABLETS  for  determining  the  degree  of  acidity  of  milk,  cream  or 

whey . Per  50 

RICHMOND’S  SLIDE  RULE  for  determining  total  solids  in  milk.  With  full  directions  for  use  .  . 
FLOATING  DAIRY  THERMOMETER,  8  inches  long . 


$2.60 

2.20 

2.40 

2.60 

1.70 


.60 

.20 


.50 

.12 

1.00 

1.00 

.15 

.16 

.15 

.26 


2.00 

2.40 

.25 

.26 

.25 

3.60 

.50 


CHEMISTRY  AND  BIOLOGY 


469 


6170 

6171 

6172 

6173 

6174 


6176 

6176 

6177 

6178 

6179 

6180 
6181 

6182 

6183 

6184 

6186 


6186 

6187 

6188 


6189 


6190 

6191 


6200 

6201 

6202 

6203 

6204 

6205 


6206 


6207 


6208 


MINERAL  COLLECTIONS 

WASHINGTON  SCHOOL  COLLECTION,  20  Minerals,  20  Rocks,  in  clothboard  case,  printed  label 

list  on  lid . per  Set 

HARDNESS  COLLECTION,  9  specimens,  each  in  tray,  all  in  oak  box.  With  smail  diamond  Per  Set 
SPECIFIC  GRAVITY  COLLECTION,  25  specimens,  large  size,  in  improved  trays  ....  Per  Set 

LUSTER  COLLECTION,  16  specimens,  large  size,  in  improved  trays . Per  Set 

MISCELLANEOUS  COLLECTION,  16  specimens,  selected  especially  to  show  Play  of  Colors,  Change 
of  Colors,  Opalescence,  Iridescence,  Tarnish,  Asterism,  Schillerization,  Fluorescence,  Phosphores¬ 
cence.  Large  size  specimens,  in  improved  trays . .  Per  Set 

FUSIBILITY  COLLECTION,  6  specimens,  large  size,  in  improved  trays . Per  Set 

COLLECTION  ILLUSTRATING  TASTE,  ODOR  AND  FEEL,  20  specimens,  large  size,  in  improved 

trays . Per  Set 

BLOWPIPE  COLLECTION,  50  most  important  species,  each  in  tray,  all  in  oak  box  .  .  .  Per  Set 

NEW  YORK  STATE  PHYSICAL  GEOGRAPHY  COLLECTION,  64  specimens,  each  in  tray,  all  in 

pine  box . Per  Set 

COLLECTION  OF  SOILS,  20  specimens,  each  in  quarter-pint  glass  show  bottle,  then  in  improved 

trays . Per  Set 

COLLECTION  OF  FUELS  AND  USEFUL  HYDRO-CARBONS  (with  Associated  Rocks  and  Fossils), 

40  specimens,  extra  large  size,  in  improved  trays . Per  Set 

ORES  OF  GOLD,  SILVER,  PLATINUM  AND  IRIDIUM,  60  specimens,  each  in  tray,  all  in  oak 

C3_g0 . . . "...  Per  Set 

COPPER  ORES  AND  MINERALS,  50  specimens,  each  in  tray,  all  in  oak  case . Per  Set 

IRON  ORES  AND  MINERALS,  60  specimens,  each  in  tray,  all  in  oak  case . Per  Set 

ORES  AND  MINERALS  OF  THE  LEAD  AND  ZINC  GROUPS  (Lead,  Tin,  Zinc,  Cadmium  and  Mer¬ 
cury),  60  specimens,  each  in  tray,  all  in  oak  case . Per  Set 

ORES  AND  MINERALS  OF  METALS  USED  FOR  ALLOYING  STEEL  (Chromium,  Cobalt,  Man¬ 
ganese,  Molybdenum,  Nickel,  Titanium,  Tungsten  and  Vanadium),  60  specimens,  each  in  tray,  all  in 

oak  case . . Per  Set 

ORES  AND  MINERALS  OF  THE  ALUMINUM  AND  MAGNESIUM  GROUPS.  (Aluminum,  Barium, 

Calcium,  Magnesium  and  Strontium),  50  specimens,  each  in  tray,  all  in  oak  case . Per  Set 

ORES  AND  MINERALS  OF  THE  ALKALI  METALS  (Caesium,  Lithium,  Sodium,  and  Potassium),  26 

specimens,  each  in  tray,  all  in  oak  case . Per  Set 

ORES  AND  MINERALS  OF  THE  NON-METALLIC  AND  SEMI-METALLIC  ELEMENTS  (Arsenic, 
Antimony,  Bismuth,  Boron,  Carbon,  Selenium,  Silicon,  Sulphur  and  Tellurium),  50  specimens, 

each  in  tray,  all  in  oak  case . Per  Set 

ORES  AND  MINERALS  CONTAINING  THE  RARE  EARTH  ELEMENTS  (Beryllium,  Cerium,  Didy- 
mium,  Erbium,  Lanthanum,  Niobium,  Scandium,  Tantalum,  Thorium,  Uranium,  Yttrium,  and 

Zirconium),  72  specimens,  each  in  tray,  all  in  oak  case . Per  Set 

ROUGH  PRECIOUS  AND  SEMI-PRECIOUS  STONES,  26  specimens,  each  in  tray,  all  in  oak 

case . Per  Set 

MISCELLANEOUS  NON-METALLIC  ECONOMIC  MINERALS,  60  specimens,  each  in  tray,  all  in 
oak  case . Per  Set 

MODELS  —  PHYSIOLOGICAL 

ENLARGED  SIZES— NATURAL  COLORS 


HUMAN  HEART :  The  anterior  wall  may  be  removed,  exposing  the  four  cavities  of  the  heart,  and  their 

openings  and  valves . 

HUMAN  EYE:  The  upper  portion,  containing  a  microscopical  representation  of  the  layers  of  the 
retina,  can  be  removed,  when  the  cornea  and  the  iris,  the  lens  and  the  vitreous  body  may  be  taken 

out . 

HUMAN  EAR:  Separates  into  parts,  showing  the  membrana  tympani,  the  ossicles  of  the  tympanum, 

the  labyrinth  and  the  half-opened  cochlea . 

HUMAN  SKIN :  Transverse  section,  showing  the  organs  of  perspiration,  a  hair  and  its  follicles,  the 

pulp,  sebaceous  glands  and  tactile  corpuscles . 

HUMAN  TEETH:  The  anterior  portion  of  the  left  maxillary  bone  is  removed  to  show  the  develop¬ 
ment  and  structure  of  the  teeth . 

HUMAN  BRAIN:  Four  views: 

a  View  of  upper  portion . 

b  View  of  the  lower  portion  (basis  of  cerebral  nerves) . 

c  View  of  perpendicular  section  along  the  median  line . 

d  View  of  transverse  section  of  the  head,  showing  the  cavities . 

HUMAN  HEAD:  Three  Views: 

a  Head  with  muscles,  nerves  and  blood  vessels  of  one  side . 

b  Cavities  of  skull  and  eye,  upper  and  lower  jaw . . 

c  View  of  perpendicular  section  of  the  head,  showing  the  brain,  cavities  of  the  mouth  and  nose, 

and  the  larynx  and  pharynx  divided  along  the  median  line . 

HUMAN  LUNGS,  with  the  heart  in  normal  position: 

a  Anterior  view  of  the  lungs  and  heart.  The  pericardium  opens  and  the  anterior  portion  of  the  left 

lung  may  be  removed,  showing  the  bronchial  ramifications,  aveoli,  etc . 

b  Posterior  view  of  the  lungs  and  heart,  with  a  representation  of  the  bronchial  ramifications,  air 

cells,  blood  vessels  and  Iobuli . 

ORGANS  OF  RESPIRATION,  AIR  PASSAGES,  LUNGS  AND  HEART:  The  anterior  part  of  both 
lungs  and  heart  removes,  laying  open  the  lungs  and  showing  the  ramifications  of  the  windpipe,  and 

the  connection  of  the  pulmonary  blood  vessels  with  the  heart . 

Continued  on  Next  Page. 


$2.50 

2.76 

22.50 

9.75 


18.25 
2.76 

9.50 

4.50 

2.50 
9.00 

22.50 

19.75 

9.50 

6.75 

10.00 

12.50 

3.76 

2.76 

9.75 

22.76 

9.25 

4.75 


$8.00 


6.50 


7.00 


3.60 

3.50 

3.25 

3.25 

3.25 

3.25 

6.50 

6.60 

5.50 


4.50 

4.60 


11.00 


470 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


PHYSIOLOGICAL  MODELS  —  Continued 


6209  HUMAN  LARYNX:  Anterior  and  posterior  views: 

a  Is  an  anterior  aspect,  showing  base  of  tongue,  hyoid  bone,  thyroid  gland,  etc . $2.76 

b  Posterior  aspect,  showing  the  glottis  and  vocal  cords .  2.76 

c  Larynx  in  connection  with  the  tongue  and  pharynx,  the  latter  is  opened  from  behind,  and  parts 

showing  mucous  membrane .  3.26 

6210  HUMAN  JOINTS:  Partially  opened,  showing  their  bones  and  ligaments: 

a  Arm-joint  of  the  shoulder,  opened .  2.60 

b  Elbow-joint,  a,  anterior  view . ✓ .  2.00 

c  Elbow-joint,  b,  lateral  view .  2.00 

d  Wrist-joint  and  hand .  2.76 

e  Hip- joint .  2.60 

f  Knee-joint  .  2.60 

g  Ankle-joints  and  foot .  3.60 

6211  HUMAN  TRUNK  (Torso),  with  viscera  of  the  chest  and  abdomen  laid  open . 32.60 

6212  HUMAN  SKULL  AND  BRAINS,  the  various  parts  of  which  can  be  taken  out . 11.00 

6213  LARYNX  PHANTOM,  mask  of  the  face  with  mouth  open .  9.50 

6216  PHYSIOLOGICAL  MODELS.  Set  Complete,  28  models  as  above  listed . 126.00 


No.  6222 


No.  6224 


No.  6226 


6220  MORTARS,  PRESSED  GLASS,  with  pestles. 


a 

Capacity,  ounces  2 

Diameter,  inches  2 % 

Each  $0.22 

6222  MORTARS  AND  PESTLES,  IRON,  urn  sha 

a 

Capacity,  pints  1 

Each  $0.60 

6224  MORTARS  AND  PESTLES,  PORCELAIN, 

a 

Diameter,  inches  2)4, 

Each  $0.33 


b 

c 

d 

4 

8 

16 

4 

4J'2 

5 

.28 

.36 

.60 

b 

c 

2 

4 

.80 

1.10 

porcelain  pestles. 

b 

c 

d  • 

4 

5  M 

7 

.48 

1.00 

1.26 

6226  MORTAR,  of  chilled  steel,  pestle  15  mm.  diameter . 

MOUNTING  PAPER.  See  PAPER,  MOUNTING,  Page  472. 

6236  MUFFLES,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.)  Highly  refrac¬ 
tory,  will  not  crack  with  sudden  and  extreme  changes  of  temperature,  absolutely  gas  tight. 

For  assaying,  ash  determinations,  ignition  of  precipitates,  and  general  analytical  and  chemical  work, 
they  are  unequalled.  Especially  valuable  for  enamelling  small  work,  hardening  and  annealing  small 
parts  and  for  general  testing  and  experimental  use. 

a  b  c  d  e  f 


Length,  outside,  inches 

^A 

6H 

9'A 

7H 

9'A 

18  M 

Width,  outside,  inches 

2  % 

3% 

4  K 

6  H 

Height,  inches 

2% 

3  y2 

5 

2% 

4  34 

5 

Each 

$1.86 

2.60 

4.26 

2.60 

3.76 

6.76 

MUSEUM  JARS.  See  JARS,  MUSEUM,  Page  461. 

6246  NEEDLE,  INOCULATING,  platinum  point  sealed  in  glass  handle . 

NEEDLES,  DISSECTING.  See  Page  433. 

6946  NESSLER’S  JARS  OR  TUBES  for  ammonia  tests  in  water  analyses;  of  colorless  glass. 

a  be 

50  100  50  &  100 

$0.66  .80  .96 


$2.00 


$0.60 


Graduated,  cc. 
Each 


CHEMISTRY  AND  BIOLOGY 


47i 


No.  6255 


No.  20-215 


No.  6296 


6248  OIL  STONE,  high  grade,  an  excellent  stone  for  scalpels . 

6256  OIL  TESTER,  Cleveland  Open  Fire  Tester,  for  high  grade  lubricating  oils.  Made  of  very  heavy 

copper  and  brass  casting,  nickel-plated . 

6266  OIL  TESTER,  ELLIOT’S,  POLISHED  COPPER  for  flash  point  determinations,  adopted  as  stand¬ 
ard  by  the  states  of  New  York,  New  Jersey,  Iowa,  Michigan,  and  in  genpral  use  everywhere 
20-215  OSMOSIS  APPARATUS,  STUDENTS’,  for  qualitative  as  well  as  quantitative  work  in  osmosis. 

The  apparatus  consists  of  an  osmosis  tube  of  design  as  illustrated,  held  adjustably  in  a  nickel-plated 
clamp  which  may  be  clamped  to  the  side  of  a  jar.  One  end  of  the  osmosis  tube  is  closed  by  a  thin 
porous  membrane  which  may  be  removed  and  replaced  from  time  to  time  as  needed. 

Apparatus  complete  as  illustrated . 

6268  OVERSLEEVES,  Chemical  and  Water-proof,  ample  in  size,  readily  adjusted  to  both  sexes.  Per  Pair 


6134  PANS,  AGATE  WARE.  a  b  c 

Dimensions,  inches  6}4  X  1J3  7  X  1/4  8}4  X  2 

Capacity,  quarts  Vi  1  2 

Each  $0.16  .18  .22 

6280  PAPER,  SAND.  a  b  c 

Fine  Medium  Medium  Coarse 

Per  Dozen  Sheets  $0.18  .18  .18 

PAPER,  FILTER.  See  FILTER  PAPER,  Page  437. 

6285  PAPER,  GLAZED,  for  use  in  laboratory,  in  color  reactions. 

a  be 

Color  White  Black  Blue 

Per  Quire  $0.30  .30  .30 

6780  PAPER,  LITMUS,  red,  in  sheets .  Per  Sheet  $0.04  Per  Quire 

6781  PAPER,  LITMUS,  red,  in  books  of  strips . Per  Book 

6782  PAPER,  LITMUS,  blue,  in  sheets .  Per  Sheet  $0.04  Per  Quire 

6783  PAPER,  LITMUS,  blue,  in  books  of  strips . Per  Book 

6290  PAPER,  PARCHMENT,  best  grade  of  vegetable  parchment . Per  Sheet 

6990  PAPER,  TUMERIC . Per  Sheet  $0.04  Per  Quire 

6292  PENCIL,  INDELIBLE,  for  marking  glass  utensils . 

6789  PENCIL,  LITMUS  . 

PETRI  DISHES.  See  DISHES,  Page  432. 


6295  PETRI  DISH  HOLDER,  POLISHED  COPPER,  with  Inside  Tray  to  lift  out.  Size  9  inches  high  by 

inches  diameter . 

PINCHCOCKS.  See  CLAMPS,  Page  423. 

6300  PINS,  INSECT,  special,  double  japanned  black,  finely  tempered  steel,  needle  points,  absolutely  fast 


heads.  a  bcdefgh 

Size  No.  00  0  1  2  3  4  5  6 

Per  100  $0.20  .20  .18  .18  .18  .18  .18  .18 

6301  PINS,  INSECT,  special,  double  plated  white  steel  pins,  finely  tempered  steel,  needle  points,  absolutely 

fast  heads.  a  bcdefgh 

Size  No.  00  0  1  2  3  4  5  6 

Per  100  $0.26  .25  .20  .20  .20  .20  .20  .20 

6302  PINS,  INSECT,  wth  yellow  heads,  japanned  steel  pins,  needle  points,  absolutely  fast  heads. 

a  bcdefgh 

Size  No.  00  0  1  2  3  4  5  6 

Per  100  $0.18  .18  .15  .15  .16  .16  .16  .15 

6303  PINS,  INSECT,  INDESTRUCTIBLE,  non-corrosive  metal,  needle  points,  absolutely  fast  heads. 

Guaranteed  not  to  corrode  under  the  most  trying  conditions. 

a  bcdefgh 

Size  No.  00  0,  1  2  3  4  5  6 

per  100  $0.30  .30  .26  .25  .26  .25  .36  .35 

6306  PIPES,  CLAY . Per  Dozen 


$0.36 

14.00 

9.00 


1.25 

.40 


$0.66 

.06 

.66 

.06 

.06 

.66 

.22 

.26 


3.50 


i 

7 

.18 

i 

7 

.20 

i 

7 

.15 


7 

.35 

$0.16 


472 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6308 


No.  6309 


No.  6322 


No.  6317 


No.  6312  No.  6313 


6313 


6314 

6317 

6318 
6090 
6322 


6322A 

6323 

6324 

6325 
6327 


6308 

6309 
6312 


PIPETTES,  Medicine  Droppers,  straight  tubes  with  pure  rubber  bulbs.  Per  Dozen  $0.35 
- ,  bent  tubes  with  pure  rubber  bulbs . Per  Dozen  .36 


6330 


6332 

6332a 

6334 

6336 

6337 

6339 

6340 
6342 


6345 


PIPETTES,  MOHR’S,  accurately  graduated 

a  b  c  d  e 

Capacity,  cc.  1  X  Vioo  2  X  ^  10  X  %  20  X  34  25  X  34 

Each  $0.36  .30  .44  .55  .62 

PIPETTES,  VOLUMETRIC,  accurately  graduated  with  one  mark. 

a  bcdefghi  j 

Capacity,  cc.  1  2  3  5  10  15  20  25  50  75 

Each  $0.09  .10  .12  .13  .17  .21  .22  .27  .33  .40 

PIPETTES,  VOLUMETRIC  WITH  STAND,  a  set  of  above  pipettes,  1,  2,  5,  10,  25,  50  and  100  cc., 

with  improved  stand . Set 

PIPETTES,  OVERFLOW,  AUTOMATIC,  with  patent  three  way  stopcock  and  reservoir  for  collecting 

the  excess  liquid.  Capacity  25  cubic  centimeters . 

- ,  capacity  100  cubic  centimeters . 

PITH  for  cutting  sections . Per  Package 

PLANT  PRESS.  This  press  is  a  simple  contrivance  by  which  a  plant  is  dried  in  a  few  hours  without  the 
troublesome  changing  of  blotters  and  shifting  of  specimens.  Consists  of  a  series  of  layers  of  tubular 
paper  inserted  between  sheets  of  blotting  paper  and  absorbent  cotton  so  that  all  the  moisture  is 

carried  off  by  a  current  of  hot  air  passing  through  the  tubes.  Size  9  X  12  inches . 

-  ci7p  1 9  V  10  lnrliPQ 

MOUNTING  PAPER,  11  X  ^'inches'  .’  .'  .’  .'  .'  .'  .'  .'  .'  .'  .’  .'  .'  .'  .'  .'  .'  .’  .'  Per  Quire 

DRYING  PAPER,  11  X  17  inches . Per  Quire 

GENUS  COVERS  for  mounting  specimens?  11 34  X  1734  inches  when  folded . Per  Quire 

PLATES,  FILTER,  ALUNDUM,  for  filtering  where  a  small  amount  of  solid  matter  is  present  in  a 
large  amount  of  liquid.  May  also  be  used  for  filtering  dust  from  air  or  flue  gases.  Porosity  43.9 
per  cent,  carried  in  stock.  Porosity  47.4  per  cent,  may  also  be  obtained  on  application.  60°  bev¬ 
elled  edge.  a  bed 

Inches  %  X  34  1  X  34 

Each  $0.28  .30 

PLATES,  GLASS  for  covers  of  bottles,  beakers,  etc. 


f 

50  X  % 

1.00 


k 

100 

.45 

$3.60 

3.26 

3.85 

.10 


1.66 

2.95 

.50 

.30 

1.00 


a 

Size,  inches  4X4 

Each  $0.03 

PLATES,  GLASS,  blue  cobalt  glass. 

- ,  4X4  inches . 


b 

X 

.04 


.40 

c 

X 

.05 


„:OOOj 
/oOOOi 
<£-5 


X  4  inches . $0.07 

. 12 


No.  6334 


PLATE,  PORCELAIN,  glazed,  11X9  centimeters,  with  twelve  cavities  for  color  reactions . $0.76 

PLATE,  PORCELAIN,  unglazed  and  porous  for  drying  crystals.  2234  cm.  diameter .  .16 

PLATE,  STREAK,  unglazed  porcelain,  634  X  5  centimeters,  for  arsenic  test,  etc .  .30 

PLATES,  PORCELAIN,  porous,  square,  for  drying  crystals  and  precipitates.  10  mm.  thick,  size 

6X6  inches .  .26 

- ,  same  as  above,  but  8X8  inches .  .66 

PLATES,  PERFORATED  GLAZED  PORCELAIN,  for  use  in  funnels. 

a  be 

Diameter,  mm.  25  38  50 

Each  $0.16  .20  .26 

PLATES,  FUSED  SILICA,  UNGLAZED.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.) 

a  b  c  d  e 

Thickness,  inch  34-34  %  34  24  34 

Per  Square  Inch  $0.03  .06  .06  .07  .08 

PLATES,  FUSED  SILICA,  GL.AZED,  34“J4  inch  thick,  in  plates  up  to  6  inches  square.  Per  Square  Inch  .08 


6346 


473 


CHEMISTRY  AND  BIOLOGY 


PLATINUM  WARE 


All  of  the  following  ware  is  hammered  to  shape,  tested  and  finished  in  the  best  manner.  It  is  guaranteed  free 
from  flaws  and  blisters  and  to  give  entire  satisfaction  in  competent  hands.  Approximate  weights  are  given  without 

price.  Prices  will  be  governed  by  the  market  price  of  platinum. 


Nos.  6364a-e 


n.  6355  No.  6357 


Nos.  6363a -k 


No.  6371 


No.  6373 


No.  6370 


No.  6375 


6350 


PLATINUM  FOIL. 

Light  Medium 

Thickness,  inch  .001  .002 

Thickness,  mm.  .03  .05 

Approximate  Weight  per  Square  Inch  0.353  0.705 

PLATINUM  WIRE.  Platinum  loops  for  chemical  laboratory  work  are  usually  made  of  No.  28  Wire,  platinum  triangles  of  Nos. 
24  or  26,  platinum  inoculating  needles  of  No.  24  and  sometimes  of  No.  20. 

B.  &  S.  Gauge  No.  18  20  22  24  25 

Diameter,  inch  .0403  .0319  .0253  .0201  .0179 

Diameter,  mm.  .81  .64  .51  .45 

Weight  per  Foot,  grams  5.365  3.404  2.081  1.330  1.077 

PLATINUM  ANODE,  spiral  %  inch  in  diameter,  made  of  .040  inch  wire,  6J-6  turns,  weight  approximately  7  grams. 

the  standard  form  and  designed  particularly  for  use  with  Cathode  No.  6357  following. 

PLATINUM  CATHODE,  diameter  of  cylinder  1  inch,  height  2  inches,  height  of  stem  2  inches,  height  over  all  4  inches.  Diam¬ 
eter  of  stem  .040  inch.  Approximate  weight  11  grams. 

PLATINUM  FILTER  CONES,  seamless,  60°,  perforations  .016  to  .025  inch. 

a  b  c  d  e  f  g 

Diameter,  inches  %  %  1  1  Vi  1  %  2 

Approximate  Weight,  grams  1  1.5  2.1  3.1  5.3  7.5  9.2 

PLATINUM  CRUCIBLES  WITH  COVERS.  A  crucible  with  cover  weighs  approximately  as  many  grams  as  it  holds  cubic 
centimeters. 

a  b  c  d  e  f 


6355 

6357 

6361 

6363 


6364  PLATINUM  CRUCIBLES,  GOOCH,  WITH  COVERS. 


Heavy 

.0035 

.09 

1.058 


26 

.0159 

.40 

0.851 


28 

.0126 

.32 

0.480 


30 

.01 

.26 

0.332 


32 

.0079 
.20 
0.213 
This  is 


g 


j 


Diameter,  cm. 

2.2 

2.5 

3.0 

3.3 

3.5 

4.0 

4.2 

4.4 

4.7 

5.0 

5.3 

Depth,  cm. 

2.2 

2.5 

3.0 

3.3 

3.5 

4.0 

4.2 

4.4 

4.7 

5.0 

5.3 

Capacity,  cc. 

8 

10 

15 

20 

25 

30 

40 

50 

60 

70 

80 

Approximate  Weight,  grams 

8 

10 

15 

20 

25 

30 

40 

50 

62 

65 

68 

Diameter,  cm. 

Depth,  cm. 

Capacity,  cc. 

Approximate  Weight,  grams 


a 

2.7 

2.7 

10 

13 


6366  PLATINUM  DISHES,  round  bottom 


b 

3.2 

3.2 

15 

18 


c 

3.3 

3.3 

20 

22 


d 

3.6 

3.6 

25 

29 


e 

3.9 

3.9 

30 

34 


a 

b 

c 

d 

e 

f 

g 

h 

i 

] 

k 

1 

3.8 

4.2 

4.4 

4.8 

5.6 

6.5 

6.5 

7.2 

7.8 

8.4 

8.9 

9.4 

1.0 

2.0 

2.2 

2.4 

2.7 

3.0 

3.3 

3.5 

3.7 

3.7 

4.1 

4.3 

15 

20 

25 

35 

50 

65 

75 

100* 

125 

150 

175 

200 

5 

6 

8 

12 

17 

22 

25 

33 

42 

50 

55 

67 

6367 

6368 

6369 

6370 

6371 
6373 
6375 


6377 

6379 

6380 

6381 


Diameter,  cm. 

Depth,  cm. 

Capacity,  cc. 

Approximate  Weight,  grams 

PLATINUM  DISHES,  without  lip,  a  to  1,  same  sizes  and  weights  as  above. 

PLATINUM  DISH  for  iron,  steel  or  water  analysis,  capacity  45  cc.,  approximate  weight  15  grams. 
PLATINUM  DISH  for  milk  analysis,  capacity  45  cc.,  approximate  weight  17  grams. 
PLATINUM  DISH  for  sugar  analysis.  Capacity  35  cc.,  approximate  weight  16  grams. 
PLATINUM  DISH  for  water  analysis.  Capacity  100  cc..  approximate  weight  20  grams. 
PLATINUM  TIPPED  FORCEPS  for  blowpipe  work  and  general  laboratory  use. 

PLATINUM  INCINERATING  DISHES. 

Capacity,  cc. 

Approximate  Weight,  grams 

PLATINUM  SPATULAS. 

Length,  cm. 

Approximate  Weight,  grams 
PLATINUM  TRIANGLES,  solid  ends 
For  Crucible,  Capacity  cc. 

Size  of  Wire,  inch 
Weight  in  Grams 

PLATINUM  TRIANGLES,  twisted  ends 

For  Crucible,  Capacity  cc. 

Size  of  Wire,  inch 
Weight  in  Grams 

PLATINUM  TRIANGLES  WITH  HOLDE 

crucible  up  to  100  cc.  a 

For  Crucible,  Capacity  cc.  10 

Size  of  Wire,  inch  .047 

Weight  in  Grams  2 


a 

b 

15 

20 

10 

14 

a 

b 

7 

10 

5 

8 

a 

b 

c 

d 

e 

f 

10 

15 

20 

30 

40 

60 

.045 

.045 

.055 

.055 

.064 

.064 

5 

8 

11 

12 

15 

18 

a 

b 

c 

d 

e 

f 

10 

15 

20 

30 

40 

60 

.045 

.045 

.055 

.055 

.064 

.064 

5 

6 

11 

12 

18 

20 

rolders  nickel-plated  and 

will  accommodate  any 

size  triangle  for  he 

b 

c 

d 

e 

f 

g 

15 

20 

30 

40 

60 

80 

.047 

.050 

.050 

.062 

.062 

.064 

2.5 

4.5 

5 

7  5 

8 

9 

h 

100 

.064 

10 


474 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


6386  PLIERS,  SIDE  CUTTING,  good  quality . 

PNEUMATIC  TROUGHS.  See  TROUGHS,  PNEUMATIC,  Page  489. 


6390  POROUS  CUPS. 

Diameter,  inches 
Height,  inches 
Each 


a 

1H 

3 

$0.16 


b 

2 

4 

.20 


No.  6386 

POTASH  APPARATUS.  See  BULBS,  POTASH,  Page  419. 
PRESSES  FOR  CORKS.  See  Page  426. 

PRESSES  FOR  PLANTS.  See  Page  472. 


c 

5 

.26 


Each  $0.40 


d 

3 

7 

.30 


6396  PUMP,  CARBOY,  for  pumping  acid  from  a  carboy  through  a  siphon.  A  carboy  inclinator  is  not  always 
safe  and  requires  considerable  care  when  used.  This  carboy  obviates  all  danger  and  will  be  found  a 
most  satisfactory  method  of  readily  transferring  acid  from  carboy  to  bottles. 

Complete . $6.00 


PYROMETERS 

INDICATING  METERS— THERMO-COUPLES 


A  Pyrometer  of  two  essential  parts,  —  the  Meter  which  indicates  or  records  the  temperature  and  the  Thermo- 
Couple  which,  on  being  placed  in  the  heat  to  be  measured,  generates  the  electromotive  force  that  actuates  the  meter. 

We  have  listed  below  two  different  types  of  meters  each  of  which  can  be  obtained  with  different  ranges  and 
graduated  in  Fahrenheit  or  Centigrade  divisions.  We  have  also  listed  various  types  of  thermo-couples.  From  among 
these  listed  it  will  be  possible  to  select  types  and  ranges  suited  to  individual  requirements.  To  insure  getting  the 
proper  outfit,  it  is  advisable  to  inform  us  in  regard  to  the  service  for  which  it  is  to  be  used. 

PORTABLE  INDICATING  METERS.  These  are  the  highest  grade  D’Ar- 
sonval  type  Milli-voltmeters  designed  especially  for  pyrometer  work.  They  are 
very  sensitive  high- torque  meters,  provided  with: 

1  Zero  Temperature  Adjustment  which  insures  that  the  meter  indicates  cor¬ 
rectly  regardless  of  the  temperature  of  the  surrounding  media. 

2  Zero  Adjustor  which  is  a  simple  device  for  setting  the  pointer  to  agree  with 
the  cold  end  temperature  of  the  Thermo-couple. 

3  Resilient  Pivot  Mounting  which  permits  the  utmost  delicacy  in  adjustment 
of  the  movement  and  by  protecting  it  from  the  effects  of  jars  and  vibra¬ 
tions,  preserves  its  accuracy. 

The  case  isjof  aluminum,  finished  in  black  enamel.  Over  all  dimensions  are 
6 M  X  6  X  3  inches.  Scales  are  SYi  inches. 


FAHRENHEIT  SCALES 

CENTIGRADE 

SCALES 

Catalogue’No. 

Range 

Degrees  per  Division 

Catalogue  No. 

Range 

Degrees  per  Division 

6397  " 

32-1000 

10 

6397A 

0-550 

5 

6398 

32-1500 

20 

6398A 

0-800 

10 

6399 

32-2000 

20 

6399A 

0-1100 

10 

6400 

32-2550 

25 

6400A 

0-1400 

20 

Nos.  6397  to  6400A 


Price,  with  any  of  the  above  standard  scales 


$38.00 


CHEMISTRY  AND  BIOLOGY 


475 


Nos.  6402  to  6406A 


WALL  INDICATING  METERS.  These  meters  are  essentially  the  same  as 
the  Portable  Meters  above  listed,  except  that  they  are  designed  with  wall  mounting. 
The  cases  are  of  aluminum,  finished  in  black  enamel.  Diameter,  6  inches,  depth 
3%  inches.  Scale  arc,  5J4  inches. 


FAHRENHEIT  SCALES  CENTIGRADE  SCALES 


Catalogue  No. 

Range 

Degrees 
per  Division 

Catalogue  No. 

Range 

Degrees 
per  Division 

6402 

32-1000 

10 

6402A 

0-550 

5 

6403 

32-1500 

20 

6403A 

0-800 

10 

6404 

32-2000 

20 

6404A 

0-1100 

10 

6405 

32-2550 

25 

6405A 

0-1400 

20 

Price,  with  any  of  the  above  standard  scales 

.  .  .  $38.00 

6407  THERMO-COUPLES.  These  thermo-couples  generate  an  electro-motive  force  five  times  greater  than 
the  costly  platinum-rhodium  couples,  have  a  practically  straight  line  temperature,  —  E.  M.  F. 
relation,  are  heavy  in  cross  section  and  are  inexpensive.  No.  14  B.  &  S.  Gauge  elements;  length 
of  couple  3  feet. 


Price  includes  handle  and  10  feet  of  flexible  leads. 

For  maximum  temperature  of  1000°  F.  (550°  C.) .  5.50 

6408  - ,  for  maximum  temperature  of  1500°  F.  (800°  C.) .  5.60 

6409  - ,  for  maximum  temperature  of  2000°  F.  (1100°  C.) .  5.50 

For  Extra  Length  Couples  add, . r . Per  Foot  .60 


6410  THERMO-COUPLES,  same  as  above,  but  No.  8  B.  &  S.  Gauge  elements  and  with  flexible  leads 


20  feet  long. 

For  maximum  temperature  of  1000°  F.  (550°  C.) .  6.75 

6411  - ,  for  maximum  temperature  of  1500°  F.  (800°  C.) .  6.76 

6412  - ,  for  maximum  temperature  of  2000°  F.  (1100°  C.) .  6.76 


6413  - ,  for  maximum  temperature  of  2500°  F.  (1400°  C.) .  6.76 

For  Extra  Length  Couples  add .  Per  Foot  .86 


6414  THERMO-COUPLES,  same  as  No.  6407  but  No.  6  B.  &  S.  Gauge  elements  and  with  flexible  leads  20 
feet  long. 

For  maximum  temperature  of  2000°  F.  (1100°  C.) .  8.35 


6415  - ,  for  maximum  temperature  of  2500°  F.  (1400°  C.) .  8.35 

For  Extra  Length  Couples  add, . Per  Foot  1.50 


6420 


PYROMETER  TUBES,  ALUNDUM.  (See  Index,  “Alundum  Ware,”  for  Characteristics.)  Supplied 
in  lengths  of  8,  12,  18,  24,  27,  30,  36,  and  39  inches.  When  ordering  Specify  Catalogue  Number, 
Length,  Bore,  and  Wall. 


Bore,  inch 

a 

7A« 

b 

%e 

c 

X 

a 

%o 

e 

X 

I 

Vs 

g 

1 

a 

1  Vs 

m 

Wall,  inch 

Vs 

%2 

Vs 

%« 

X 

X 

X 

Via 

X 

Per  inch 

$0.28 

.34 

.28 

.28 

.34 

.34 

.45 

.45 

.50 

6425 


RECALESCENT  OUTFIT,  —  a  simple  and  re¬ 
liable  apparatus  for  determining  the  proper 
hardening  temperatures  of  carbon  steel  (high 
carbon  steels  only).  The  apparatus  consists 
of  an  Electric  Furnace,  a  Pyrometer  and  a 
Rheostat  for  regulating  the  furnace  tem¬ 
perature. 

The  operation  is  to  clamp  two  small  pieces  of 
steel  to  the  end  of  the  thermo-couple,  place 
them  in  the  electric  furnace  and  heat  until 
the  “recalescent”  or  “critical”  point  is 
passed  as  indicated  by  the  pyrometer. 

Outfit  complete  with  Electric  Furnace  No. 
6482A  (see  page  440),  for  110  or  220  Volts 
A.  C.  (60  cycles)  or  D.  C.  ........ 

Note.  —  When  ordering,  specify  Line  Volt¬ 
age  and  whether  A.  C.  or  D.  C. 


$70.00 


PYKNOMETERS.  See  BOTTLES,  SPECIFIC  GRAVITY,  Page  418. 


No.  6425 


476 


KNOTT  APPARATUS  CO 


BOSTON 


RADIOGRAPHS 

The  following  list  of  RADIOGRAPHS  has  been  carefully  made  from 
the  complete  selection  of  one  of  our  large  hospitals,  for  the  purpose  of 
showing,  first,  the  possibilities  of  correct  X-Ray  examination  and,  second, 
to  show  the  formation  of  joints  in  the  study  of  Physiology. 

6430  FORMATION  OF  JOINTS,  (a)  Child’s  Hand,  showing  Epiphy¬ 

sis;  (b)  Adult  Hand;  (c)  Elbow  Joint  (Lateral  view);  (d)  Hip 
Joint;  (e)  Knee  (Lateral  view);  (f)  Ankle  (Lateral  view). 

6431  FRACTURES  AND  FOREIGN  BODIES,  (a)  Hand  (Fracture 

Metacarpal  Bones);  (b)  Fore  Arm  (Fracture  Ulna  and  Radius); 
(c)  Leg  (Fracture  Tibia  and  Fibular);  (d)  Hand  with  Needle 
Embedded;  (e)  Wrist  (Typical  Fracture);  (f)  Foot  (Fractured 
Metatarsal). 

Each . $1.00  Choice,  any  six  ...  .  $6.60 

Complete  Series,  Nos.  6430  and  6431  .  10.00 

6432  RADIOGRAPHS.  A  selected  list  of  various  articles  photo¬ 

graphed  on  one  plate  to  show  the  different  degrees  of 


radiability  of  diverse  substances 


1.76 


No.  6430f 


6435 

6440 

6446 

6446 

6448 

6450 

6460 

6461 

6463 

6464 

6466 

6468 

6472 


Nos.  6445a-c 
RECEIVERS,  RETORT. 

Capacity,  ounces  4  8  16 

Each  $0.10  .14  .20 

RETORTS,  COPPER,  for  generation  of  oxygen,  etc.  a  bed 

Capacity,  ounces  8  16  32  64 

Each  $2.25  2.60  3.36  3.96 

RETORTS,  GLASS,  plain,  without  tubulations  and  glass  stoppers.  a  b  c 

Capacity,  ounces  8  16  32 

Each  ...  ...  ... 

RETORTS,  GLASS  with  glass  stoppers  ground  in.  a  b  c  d  e 

Capacity,  ounces  4  8  16  32  48 

Each  ...  ...  ...  ...  ... 

RETORTS,  IRON,  for  distilling  mercury,  etc.  a  be 

Capacity,  ounces  8  16  32 

Each  $2.25  2.50  2.95 

RETORTS,  VITRIFIED  PORCELAIN,  with  tubulature  and  stopper.  a  be 

Capacity,  cc.  140  210  275 

Each  $2.60  4.00  4.36 

RINGS  FOR  RING  STANDS,  Harcourt  Open  Side  Filter  Rings,  short  shank  for  use  on  small  and 
medium  stands.  a  be 

Diameter,  inches  2  3  4 

Each  $0.13  .16  .20 

RINGS  FOR  RING  STANDS,  Harcourt  Open  Side  Filter  Rings,  long  shank  for  use  on 
large  stands.  a  bed 

Diameter,  inches  2  3  4  5 

Each  $0.14  .17  .21  .25 

RINGS  FOR  RING  STANDS,  short  shanks  for  use  on  small  and  medium  stands. 


Nos.  6436a-c 


f 

64 


a  b 

Diameter,  inches  2  3 

Each  $0.10  .13 

RINGS  FOR  RING  STANDS,  long  shank  for  use  on  large  stands. 

Diameter,  inches 
Each 

EXTENSION  RINGS,  OPEN  SIDE  (Harcourt  Open  Side  Filter  Rings), 
quire  the  use  of  Clamp  Holder  No.  4011.  a  b 

Diameter,  inches  2  3 

Each  $0.13  .15 

RINGS,  EXTENSION,  for  use  with  No.  4011  Clamp  Holder. 

a  b 

Diameter,  inches  2  3 

Each  $0.11  .13 

RINGS,  CONCENTRIC,  of  cast  iron,  japanned,  with  clamp  for  use  on  ring 
or  retort  stands,  to  support  funnels,  flasks,  etc.  a  b 

No.  of  rings  3  4 

Diameter  of  Largest  Ring,  inches  6  8 

Set  $0.70  .90 


Nos.  6460a-c 


CHEMISTRY  AND  BIOLOGY 


477 


6480 


6482 


6484 


RODS,  GLASS,  in  lengths  of  one  meter. 
Diameter,  mm. 

Per  Pound 

RODS,  GLASS,  Stirring  Rods,  finished  ends. 
Size,  mm. 

Per  Dozen 


6486 

43-220 


6490 


a 

4 

$0.60 


b 

5 

.60 


c 

6 

.50 


yt  iso 

$0.16 


b 

X  150 

.20 


r./ 

% 

1.25 


f 

3/8 

1.40 

Per  Box 
Foot 


d 

7 

.50 


RODS,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.)  Can  be 
used  for  stirring  and  pouring  at  high  temperatures,  particularly  in  the  case  of  high 
melting  metals  and  alloys  which  do  not  form  basic  oxides.  In  lengths  up  to  6  feet, 
a  bed 

Diameter,  inch  Vk  %  M 

Per  Foot  $0.40  .50  .75  1.00 

RUBBER  BANDS,  assorted  sizes . 

RUBBER  DAM,  thin  sheet  rubber,  best  quality . Per  Square 

RUBBER  DISCS,  a  tough  sheet  rubber  especially  selected  for  foot  bellows. 

Catalogue  Number  3702  3702A  3702B 

Diameter,  inches  9%  11 24  1 4J4 

Each  $0.95  1.36  1.95 

RUBBER  POLICEMEN  for  scraping  precipitates  from  the  sides  of  beakers,  etc.  For 
use  on  glass  rods.  Pure  rubber,  without  glass  rod  . Each 


$0.15 

.33 


.08 


No.  6490 


THE  KNOTT  QUALITY 

ANTIMONY  RUBBER  TUBING 
AND  STOPPERS 


We  early  realized  that  the  reason  why  France,  Germany  and  England  were  supplying  practically  all  of  the  rub¬ 
ber  tubing  and  stoppers  used  in  chemical  laboratory  work,  was  due  to  research  devoted  to  this  branch  of  chemical 
industry.  We,  therefore,  secured  the  services  of  chemists  eminently  well  fitted  to  undertake  this  line  of  work,  in 
order  to  find  out  the  reason  why  rubber  of  equal  quality  could  not  be  produced  in  this  country.  These  researches 
resulted  in  our  well-known  Formula  “317,”  on  which  our  laboratory  rubber  for  the  past  sixteen  years  has  been  based 
Many  laboratories  have  not  yet  appreciated  the  fact  that  cheap  rubber  is,  in  the  end  the  more  expensive  Both 
economy  and  efficiency  in  laboratory  organization  make  it  eminently  desirable  to  use  the  bef  rubber  ob tamable. 
In  ordering,  specify  Knott’s  “317”  Antimony  Rubber,  and  thus  be  sure  of  obtaining  a  rubber  of  the  highest  quality. 


6500  KNOTT’S  “317”  ANTIMONY  RUBBER  TUBING,  regular 
thickness  of  wall,  extraordinary  quality. 

Inside  diameter,  inch  24  %  24  24  %  % 

Price  per  Foot  $0.06  .08  .12  .16  .17  .26 

6502  KNOTT’S  “317”  ANTIMONY  RUBBER  TUBING,  same 
quality  as  above,  but  extra  thickness  to  withstand  pres- 
sures.  _  . 

Inside  Diameter,  inch  24  /%  A 

Price  per  Foot  $0.10  .18  .20 

6610  FLEXIBLE  STEEL  GAS  TUBING,  for  gas  supply,  connec¬ 
tions  to  hot  plates,  gas  stoves,  gas  burners,  etc.  This 
tubing  is  practically  indestructible,  is  gas  tight  and  will 
not  kink.  Inside  diameter  24-inch,  and  carried  in  stock 
in  two  and  three-foot  lengths  only,  each  length  with 
rubber  ends  for  connecting  to  gas  cock  and  burner 
nipples.  a  b 

Length,  feet  2  ~ 

Per  Length  $0.22  -30 


.40 


H 

.25 


478 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


KNOTT’S  “317” 

ANTIMONY 
RUBBER  STOPPERS 

No.  6515 

In  order  to  simplify  the  method  of  determining 
the  size  of  rubber  stopper  desired  for  a  specific 
purpose,  our  stoppers  are  given  a  number  corre¬ 
sponding  to  the  small  diameter  in  millimeters. 
Hence,  the  stopper  K25  means  a  stopper  25  milli¬ 
meters  in  diameter. 

In  ordering  specify  the  number  according  to 
our  list  and  insist  on  Formula  “317”  if  you  wish  a 
stopper  of  the  very  highest  grade. 

We  carry  in  stock  rubber  stoppers,  solid,  with 
one  hole  and  with  two  holes  as  indicated  below. 


Size 

Diameter 

Mean 

Price 

Size 

Diameter 

Mean 

Price 

No. 

Small  End  Diameter 

Length 

Per  100 

No. 

Small  End  Diameter 

Length 

Per  100 

Kll 

11  mm. 

12  mm. 

22  mm. 

solid 

or 

1  hole 

$3.00 

K28 

28  mm. 

30  mm. 

30  mm. 

solid,  1  or 

2  holes 

$15.00 

K13 

13 

15 

22 

solid 

or 

1  hole 

4.00 

K30 

30 

33 

30 

solid,  1  or 

2  holes 

20.00 

K15 

15 

17 

25 

solid, 

1 

or  2  holes 

5.00 

K33 

33 

37 

28 

solid,  1  or 

2  holes 

23.00 

K17 

17 

19 

25 

solid, 

1 

or  2  holes 

6.00 

K37 

37 

41 

28 

solid,  1  or 

2  holes 

31.00 

K19 

19 

21 

25 

solid. 

1 

or  2  holes 

7.00 

K40 

40 

44 

30 

solid,  1  or 

2  holes 

40.00 

K21 

21 

23 

25 

solid, 

1 

or  2  holes 

9.00 

K43 

43 

46 

32 

solid  only 

46.00 

K23 

23 

25 

30 

solid . 

1 

or  2  holes 

11.00 

K47 

47 

50 

32 

solid  only 

48.00 

K25 

25 

28 

30 

solid, 

1 

or  2  holes 

14.00 

K51 

51 

53 

32 

solid  only 

56.00 

6516  RUBBER  STOPPER,  No.  1  Yi  for  Dr.  Boles’  Hospital  Bottle  as  used  at  Boston  City  Hospital.  Each  $0.36 


6923 

6520 

6522 

6524 

6526 

6530 


6531 


6532 

6533 
6535 


SACCHAROMETER,  DR.  EINHORN’S  FERMENTATION,  with  graduated  test  tube.  With  direc¬ 
tions  . 

SCISSORS,  for  general  utility,  fine  grade . 

SCOOP,  HORN,  4X2H  inches . 

SHEARS,  METAL  CUTTING,  cutting  blade  2 y2  inches . 

SHEARS,  PAPER,  superior  quality.  Cutting  blade  10  inches  long . 

SIEVES,  SEAMLESS  BRASS  FRAMES,  BRASS  GAUZE,  substantially  constructed  for  mixing  or 
separating  substances  into  different  grades  of  fineness.  These  sieves  are  made  so  that  one  will  nest 
with  the  other.  Five  inches  diameter.  a  b  c  d  e 

Mesh  10  20  40  60  80 

Each  $1-20  1.25  1.36  1.46  1.66 

SIEVES,  SEAMLESS,  BRASS  FRAMES,  BRASS  GAUZE,  same  as  above  but  8  inches  diameter. 

a  b  c  d  e  f 

Mesh  10  20  40  60  80  100 

Each  $2.30  2.30  2.40  2.50  2.60  3.00 

SIEVES,  SEAMLESS,  BRASS  FRAMES,  BRASS  GAUZE,  nested,  5  inches  in  diameter,  20,  40,  60,  80 

and  100  mesh,  with  brass  pan  and  cover.  Same  sieves  as  Nos.  6530b-f .  Per  Set  of  Five 

SIEVES,  SEAMLESS,  BRASS  FRAMES,  BRASS  GAUZE,  nested,  8  inches  in  diameter,  20,  40,  60 
80  and  100  mesh,  with  brass  pan  and  cover.  Same  sieves  as  Nos.  6531b-f.  .  .  Per  Set  of  Five 


$0.76 

.65 

.18 

.76 

1.00 


f 

100 

1.70 


8.40 

14.60 


SIEVES,  WOOD  FRAME,  BRASS  GAUZE,  diameter  6  inches. 

Mesh 

Each 


a 

30 

$0.70 


b 

40 

.76 


c  d 

60  80 

.85  1.00 


CHEMISTRY  AND  BIOLOGY 


479 


No.  6586  Nos.  6580a-c  No.  6560  No.  6562 


32-200  SIPHON,  GLASS,  plain . $0.20 

32-206  SIPHON  WITH  SUCTION  TUBE,  glass . 36 

SLEEVES.  See  OVERSLEEVES,  Page  471. 

6542  SOLDERING  OUTFIT.  Comprises  one  bar  of  solder,  one  box  of  resin,  scraper  and  a  special  solder¬ 

ing  copper  of  sufficient  size  to  retain  heat  and  designed  so  that  it  may  either  be  heated  as  an  ordinary 

soldering  copper  or,  when  attached  to  a  gas  burner,  the  gas  will  pass  through  a  hollow  tube  within 

the  length  of  the  handle  and  is  ignited  at  emission  holes  immediately  beneath  the  copper.  In 
wooden  box .  1.00 

6543  SOLDERING  OUTFIT,  similar  to  above,  except  that  the  soldering  copper  is  not  adapted  to  a  gas 

burner  and  is  not  quite  so  highly  finished.  In  wood  box .  .76 

6544  SOLDERING  COPPER,  with  handle,  one-half  pound  size .  .60 

6645  SOLDER,  stick  form . Per  Pound  .46 

6646  SOLDER,  Wire  Form  with  Resin  Cutter.  No  flux  required . Per  Pound  .50 

6547  SOLDERING  PASTE,  ACID .  Box  .25 

6648  SOLDERING  FLUID,  ACID . Bottle  .26 

SOLDERING  IRON,  ELECTRIC.  See  ELECTRIC  APPLIANCES,  Page  436. 

6550  SOLDERING  IRON  HEATER,  for  coal  gas,  a  necessity  for  the  laboratory  work  room .  1.60 

6661  - ,  same  as  above  for  gasoline  gas . .  1.86 

SOXHLET’S  APPARATUS.  See  EXTRACTION  APPARATUS,  Page  436. 

6560  SPATULAS,  HORN,  double.  a  b  c 

Length,  inches  4  5  6 

Each  $0.12  .16  .19 

6562  SPATULA,  RUBBER,  OSTWALD’S.  This  is  a  superior  instrument  and  will  be  found  practically 

indestructible . -40 

6664  SPATULAS,  STEEL  with  wood  handle.  Flexible  polished  steel  blade. 

a  b  c 

Length,  inches  3  4  6 

Each  $0.22  .27  .40 

SPECIMENS  AND  SPECIMEN  MOUNTS.  See  Page  480. 

6670  SPLINTS,  100  in  package,  selected  lengths . Per  Package  .16 

6672  SPONGES  for  general  laboratory  use.  These  sponges  are  of  excellent  quality  selected  of  convenient 

size  and  to  give  long  service . Each  .18 

6674  SPOONS,  DEFLAGRATING,  of  heavy  iron,  handles  16  inches  long. 

a  b 

Diameter  of  Spoons,  inch  % 

Each  $0.08  .10 

6576  SPOONS,  DEFLAGRATING,  of  heavy  brass,  handles  16  inches  long. 

a  b 

Diameter  of  Spoons,  inch  Yi  % 

Each  $0.12  .15 

6678  SPOON,  HORN,  with  Spatula  End,  length  5  inches . 15 

6580  SPOONS,  PORCELAIN  with  SPATULA  END,  glazed. 

a  b  c 

Length,  mm.  110  150  170 

Each  $0.20  .26  .30 

6682  SPATULAS,  PORCELAIN,  with  spatula  on  each  end,  glazed. 

a  b  c 

Length,  mm.  105  130  160 

Each  $0.20  .25  .30 

6686  SPOON,  SODIUM,  Sodium  Capsule,  after  Brownlee  and  Others.  With  ramrod . 3 


480 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


Nos.  6610a-d 


6610  SPECIMEN  MOUNTS,  KNOTT’S  PROTECTED  BOTANICAL.  Consist  of  two  parts,  —  a  thin  plate 

of  photographic  glass  to  which  narrow  flaps  of  linen  morocco  paper  are  neatly  fastened,  and  a  card¬ 
board  back  to  which  is  glued  a  thin  layer  of  sterilized  surgical  cotton  in  which  the  specimens  may  be 
embedded.  abed 

Size,  inches  5X6  634  X  834  8  X  12  12  X  16 

Each  $0.24  .28  .42  .70 

6611  SPECIMEN  MOUNTS,  KNOTT’S  PROTECTED  ENTOMOLOGY,  suitable  for  mounting  and  pre¬ 

serving  specimens  of  butterflies,  beetles  and  insects  of  all  kinds,  or  of  plants  too  large  for  Botanical 
mounts.  Consist  of  two  parts,  —  the  mounting  part  a  heavy  cardboard  tray  lined  with  a  heavy  pad  of 
cotton,  and  the  cover,  designed  to  fit  dust-proof  over  the  mounting  part,  is  designed  with  a  photo¬ 
graphic  glass  top  which  permits  of  inspection  of  specimens.  This  cover  portion  is  covered  with 
black  binding  cloth. 

a  b  c  d  e  f  g  h 

Size,  inches  234  X  3  334  X  434  4  X  5  5  X  6  634  X  634  634  X  834  8  X  12  12  X  16 
Each  $0.16  .18  .20  .24  .28  .36  .50  1.00 


SPECIMENS 

No.  6620 


Much  care  has  been  expended  on  the  preparation  of  our  zoological  material,  so  that  it  will  be  suitable  for  ele¬ 
mentary  courses.  It  is  to  be  strongly  recommended  for  its  practical  value.  We  try  to  keep  live  specimens  and  the 
prices  are  approximately  the  same  as  those  of  the  preserved  material 


National  Biology  Sheet.  Each  Dozen  100 

a  —  R10  —  Amoeba  Microscopic  Slides,  specially  prepared . $1.00  $10.00  $75.00 

b  —  Z10  — -  Grantia  (Simple  Sponge)  . 10  .35  2.60 

c  —  Z20  — •  Hydra  (fusca  or  viridis) . 25  1.60  10.00 

d  — Z21  —  Metridium  (Sea-anemone) . 25  2.00  15.00 

e  — - Medusa  of  Obelia,  slides  stained.  (Admirable  for  showing  Medusa  structure)  .  .  .60  7.00 

f  — - Medusa  (Small,  Gonionemus) . 16  1.00  8.00 

g  — - Medusa  (Large,  Aurelia) . 40  3.00  20.00 

h - Coral  (Species)  ? . 10  .75  6.00 

i  —  Z30  —  Earthworm  (Lumbricus) . 10  .76  6.00 

j  —  Z32  —  Sandworm  (Nereis  viridis) . 16  1.26  10.00 

The  sandworms  are  killed  and  hardened  bv  a  special  process  which  renders  the  tis¬ 
sues  firm.  They  are  admirably  suited  for  dissection  and  the  preparation  of  cross- 
sections.  They  are  far  superior  to  the  ordinary  formalin  material. 

k  —  Z40  —  Starfish  (Asterias)  medium  size,  dry  or  formalin . 16  1.00  8.00 

1 - Sea  Urchin . 16  1.00  8.00 

m  —  Z50  —  Crayfish  (Cambarus) . 16  1.00  8.00 

n  —  Z52  — •  Lobster  (Homarus)  chicken . 76 

o  —  Z54  —  Large  Florida  Grasshoppers . 20  1.60  10.00 

These  afford,  in  our  opinion,  the  very  best  material  for  insect  dissection.  We  so¬ 
licit  a  trial  order. 

p  — - Crickets . 10  .76  5.00 

q  — - Roaches . 10  .76  6.00 

r  — - Spider  (Epeira) . 10  .76  5.00 

s  —  Z60  —  Clam  (Mya) . 05  .60  3.00 

t  — - Snail  (Large  European) . 10  .76  5.00 

u  — - Chart  of  Mollusca . 1.60 

v  — - Amphioxus  . 26  1.50  10.00 

w  — - Necturus  . 50  5.00 

x  —  V21  —  Frogs  (very  large) . 50  6.00 

v  — - Medium  Size . 20  2.00 


> 


6624  SCHOOL  COLLECTION  of  70  SPECIES  OF  INSECTS.  Collection  especially  selected  to  represent 

all  of  the  Principal  Order.  Complete  Collection .  6.00 


CHEMISTRY  AND  BIOLOGY 


481 


6630 


6631 


$0.05 


STENCIL,  HARCOURT  IMPROVED.  Consists 
of  a  flexible  transparent  plate  with  various 
“cut-outs”  representing  outlines  of  chemical 
utensils  as  illustrated.  The  ruling  edges  of  the 
obtuse  angle  serves  as  convenient  guides  in 
drawing  delivery  tubes.  One  edge  has  a  metric 
scale  for  dimensions.  Recommended  by  prom¬ 
inent  teachers  of  chemistry  in  that  its  use 
eliminates  bad  drawings,  saves  time,  inspires 
the  pupil,  holds  his  attention  and  induces  ac¬ 
curate  thinking . Each  $0.10 

Per  Dozen  1.00 


STENCIL  CUT-OUTS,  three  sizes  Flat  Bottom 
Flasks,  Erlenmeyer  Flask,  Bottle,  Plain  Beaker, 

Griffin  Beaker,  Thistle  Top,  Funnel,  Evaporat¬ 
ing  Dish,  Bunsen  Burner,  Crucible  and  Re-  No.  6630 

tort.  Of  transparent  material,  same  shapes  and 

sizes  as  cut-outs  of  stencil  illustrated  above.  Per  Package  of  13  Cut-outs . 


STERILIZERS 


No.  6642 


No.  6644 


6640  STERILIZER,  HOT  AIR,  of  sheet  iron,  double  wall  with  enclosed  base  and  extra  asbestos  mat.  In¬ 
side  measurements,  10  inches  high,  12  inches  wide  and  10  inches  deep.  Extreme  height,  including 
base,  2llA  inches.  With  two  shelves . *  •  '  ‘  * 


6642 


6644 


With  two 

STERLIZER,  HOT  AIR,  of  sheet  iron,  double  wall,  outer  wall  covered  with  asbestos.  Heated  by  a 
row  of  small  Bunsen  Burners  around  the  sides  of  the  base,  insuring  an  even  circulation  of  heat.  I  he 
air  is  introduced  through  openings  on  each  side.  Inside  dimensions,  19  inches  high,  12  inches  w  , 

9 A  inches  deep.  With  three  shelves . 

STERILIZER.  ELECTRIC,  HOT  AIR,  automatic  control.  Constructed  of  asbestos  board  and  with 
heavy  brass  binding.  Range  50  to  200  degrees  Centigrade;  regulation  positive  and  control  within 
one  degree.  Consumption  5  amperes.  All  contact  points  are  outside  of  the  oven,  thus  eliminating 
any  possible  danger  when  using  a  combustible  substance.  Heating  units  are  independent  and  can 
be  renewed  Sizf  10  X  10  X  12  inches  wide.  Complete  for  110  volts  either  D.  C.  or  A.  C.  with 
6  feet  of  cord  and  with  plug  for  any  ordinary  socket . 


Nos.  62-70a-e 


62-70  STILLS  (DISTILLING  APPARATUS). 

Consists  of  a  heavy  copper,  tin-lined  still 
with  removable  head,  connected  with  a 
pure  block  tin  worm,  enclosed  in  a  zinc 
condensing  vessel,  having  proper  inlets 
and  outlets. 


No.  62-80 


a 

Capacity,  gallons  34 

Still  and  Condenser  $10.60 

6661  STILLS,  only,  of  above  outfit.  a 

Capacity,  gallons  34 

Each  $6.60 


b 

c 

d 

e 

1 

2 

3 

5 

12.40 

14.60 

19.76 

26.60 

b 

c 

d 

e 

1 

2 

3 

5 

6.26 

7.26 

10.00 

14.26 

62-80  STILL,  ACME.  This  still  is  a  perfect  apparatus  for  the  production  of  pure  water  by  distillation. 

The  distillate  is  cold,  and  aerated  if  desired.  The  apparatus  is  of  first-class  workmanship  throughout 
and  is  made  of  copper  and  brass,  tin-lined  and  nickel-plated.  The  gas  and  water  connections  are 
extremely  simple.  The  Acme  Water  Still  runs  automatically  and  there  is  nothing  to  get  out  of 
order.  It  is  started  and  stopped  in  a  moment.  The  “Acme”  is  comparatively  the  fastest  and  most 
economical  Water  Still,  as  it  produces  a  gallon  of  distilled  water  in  about  134  hours,  at  a  cost  of 
about  134  cents  per  gallon.  It  is  the  most  durable  still,  and  will  practically  last  a  life-time,  as  the 
mineral  and  other  matter  that  remains  in  the  retort  is  drained  off  through  the  flushing  outlet,  this 
being  done  in  a  moment  without  any  trouble  and  without  displacing  the  still  or  taking  it  to  pieces. 

The  combustion  of  gas  with  our  special  burner  is  perfect  and  all  the  heat  is  fully  utilized.  Wall 
space  required  4X12  inches,  extreme  width  8  inches,  projection  14  inches. 

Still  as  illustrated  with  burner  for  coal  or  water  gas,  natural  gas,  or  acetylene . $24.60 

STILL,  MERCURY,  HARCOURT  ECONOMY,  for 
use  on  any  110  volt  A.  C.  or  D.  C.  circuit,  ready  for 
use  as  soon  as  filled  and  connected  to  lighting  cir¬ 
cuit  current,  automatically  shut  off  when  mercury  in 
the  retort  is  exhausted.  Operating  cost  approxi¬ 
mately  one  cent  per  pound  of  distilled  mercury. 

The  impure  mercury  is  vaporized  in  an  iron  retort  sur¬ 
rounded  by  a  heating  unit  having  proper  and  ample 
electrical  and  heat  insulation.  This  entire  unit  is 
surrounded  with  a  polished  metal  casing  which 
serves  both  to  protect  the  insulation  surrounding  the 
heating  unit  and  to  prevent  unproductive  radiation. 

The  vaporized  mercury  passes  down  into  the  condensing 
chamber  located  in  the  base.  This  chamber  is  entirely 
surrounded  by  a  water  jacket  in  which  a  continuous 
stream  of  cold  water  is  allowed  to  circulate.  Com¬ 
plete  condensation  is  produced  and  the  clean  distilled 
mercury  is  drawn  off  as  desired  through  the  steel 
spigot  connected  to  the  chamber. 

The  glass  globe  shown  in  the  illustration  and  supplied 
with  the  instrument  is  not  an  essential  feature,  but 
is  used  as  a  precautionary  measure  to  make  doubly 

sure  that  no  mercury  fumes  can  possibly  reach  the  room  atmosphere . $14.00 


CHEMISTRY  AND  BIOLOGY 


483 


Nos.  6662a-c 


No.  6664 


No.  6667 


No.  6668 


STOPCOCKS,  BRASS.  See  KNOTT’S  GAS  COCKS,  Page  446. 

6660  STOPCOCK,  GLASS,  FRESENIUS’  FORM.  Bore  one  mm . Each  $1.26 

6662  STOPCOCKS,  GLASS,  GEISSLER’S.  Straight  cocks  carefully  ground  in  by  hand. 

a  b  c 

Diameter  of  Bore,  inches  12  3 

Each  $0.96  1.20  1.40 

STORAGE  BATTERY  HYDROMETERS.  See  Page  448. 

6664  STOVE,  GAS,  top  12  X  12%  inches,  height  5  inches,  finished  in  black,  drip  pan,  drawing  out  in  front, 

valves  and  supply  pipes  nickel  plated  and  polished .  4.60 

6666  - ,  two  burners,  top  22%  X  12  inches,  height  5  inches .  6.60 

6667  STOVE  (HOT  PLATE),  ELECTRIC,  ROUND.  Operates  on  110  or  220  Volts  A.  C.  (60  cycles)  orD.  C. 

Life  of  heating  element  guaranteed  for  one  year. 

Diameter,  6  inches,  pressed  steel  top,  heavy  bent  wire  legs,  “blued”  steel  finish.  Boils  one  liter  of  water 
from  cold  in  15  minutes.  Maximum  temperature  483°  C.  (900°  F.).  Current  consumption  500  watts. 

With  6  feet  Twin  Conductor  Flexible  Cord  and  detachable  Connector  Plug  (110  or  220  volts  A.  C. 


or  D.  C.) .  6.76 

6667A  EXTRA  HEATING  UNIT  for  above . < .  3.36 

Note. — When  ordering  specify  Line  Voltage  and  whether  A.  C.  or  D.  C. 


6668  STOVE  (HOT  PLATE),  ELECTRIC,  SQUARE,  similar  to  above,  but  12  inches  square.  Sheet  steel 
top,  cast  iron  legs,  “blued”  steel  finish.  Centrally  heated  by  spiral  resistance  unit  covering  circular 
area  5%  inches  in  diameter. 

Maximum  temperature  at  center,  260°  C.  (500°  F.),  temperature  at  edge  121°  C.  (250°  F.).  Current 
consumption  500  watts.  With  6  feet  Flexible  Twin  Cord  and  detachable  Connector  Plug  ....  9.00 

6668A  EXTRA  HEATING  UNIT  for  above .  3.36 

Note. — When  ordering  specify  Line  Voltage  and  whether  A.  C.  or  D.  C. 


484 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6670 


6670  STOVES  (HOT  PLATES) ,  THREE  HEAT  ELECTRIC 

for  use  on  110  01  220  Volts  A.  C.  (60  Cycles)  or  D.  C. 
Life  of  heating  unit  guaranteed  for  one  year. 

Sheet  steel  top  and  legs.  “Blued  steel”  and  black 
enamel  finish. 

Renewable  resistance  units  composed  of  three  parallel 
windings  each  connected  by  a  snap  switch  on  front 
of  plate,  heat  distribution  uniform.  Low  heat  ob¬ 
tained  with  one  switch  on,  medium,  with  two 
switches  on,  high  heat,  with  three  switches  on. 
Low,  246°  C.  (475°  F.);  medium,  316°  C.  (600°  F.); 
high,  399°  C.  (750°  F.) 


Size  of  Plate,  inches 

t 

Current  Consumption,  watts 
Price,  110  or  220  Volts,  A.  C.  or  D.  C. 

Note.  —  When  ordering  specify  Line  Voltage 


a 

12  X  18 

Low  Medium  High 
600  1200  1800 

$30.60 

and  whether  A.  C.  or  D.  C. 


Low 

1200 


b 

18  X  24 
Medium  High 
2400  3600 

47.00 


6671  EXTRA  HEATING  UNITS  for  above . 

Note.  —  No.  6670a  requires  one  unit,  but  No.  6670b  requires  two  units. 


Each  $11.26 


STOVES,  GAS.  See  also  pages  200  to  202. 

STROP.  See  MICROTOME  KNIFE  STROP,  Page  466. 


No.  6687 


No.  6689 


SUGAR  HYDROMETERS.  See  Nos.  6674A  to  C,  Page  448. 


6679  SUPPORT,  FUNNEL,  as  designed  at  Harvard  College.  A  strip  of  hardwood  with  four  beveled  holes 
for  60°  funnels.  A  V-Clamp  attached  to  the  index  side  of  this  strip  permits  of  attaching  to  the 
rods  of  supports  Nos.  6691  and  6692  . $0.46 


6681  SUPPORT,  FUNNEL,  for  6  funnels.  H  Metal  Base,  metal  upright  rod,  wood  funnel  holder,  with 


clamp  .  1.96 

6681A  WOOD  FUNNEL  HOLDER,  as  used  on  above  stand .  1.10 

6682  SUPPORT,  FUNNEL,  for  4  funnels . ' .  1.80 

6682A  WOOD  FUNNEL  HOLDER,  as  used  on  above  stand .  .96 

6683  SUPPORT,  FUNNEL,  for  2  funnels .  1.70 

6683 A  WOOD  FUNNEL  HOLDER,  as  used  on  above  stand . 86 

6686  SUPPORT,  GAY-LUSSAC’S  IMPROVED,  of  hardwood,  cork-lined  clamp  with  long  J4~inch  ex¬ 

tension  rod .  1.26 

6687  SUPPORT,  SCHELLBACH’S  UNIVERSAL,  of  hardwood,  cork-lined  clamp  with  universal  move¬ 

ment,  height  of  clamp  adjustable .  1.33 

6689  SUPPORT,  PIPETTE,  REVOLVING,  for  12  pipettes,  of  hardwood .  2.20 


CHEMISTRY  AND  BIOLOGY 


485 


No.  6691 


No.  6692 


No.  6695b 


No.  6701 


6691  SUPPORTS',  RING  OR  RETORT,  with  Rectangular  Base  and  Rod.  Base  of  iron,  neatly  japanned,  cop- 


pered  steel  rod. 

a 

b 

c 

Small 

Medium 

Large 

Rod,  inches 

18 

24 

36 

Rectangular  Base  and  Rod 

$0.32 

.42 

.60 

6692 

SUPPORTS,  RING  OR  RETORT,  with  Tripod  Base  and  Rod.  Of  iron 

1,  tripod  japai 

pered  steel. 

a 

b 

c 

Small 

Medium 

Large 

Rod,  inches 

18 

24 

36 

With  Tripod,  each 

$0.30 

.42 

.58 

6694 

SUPPORTS,  RING  OR  RETORT  with  HARCOURT  OPEN  SIDE  FILTER  RINGS. 

a 

b 

c 

Small 

Medium 

Large 

No.  of  Rings 

2 

3 

4 

Diameter  of  Rings,  inches 

2  &  3 

2,  3  &  4 

2,  3,  4  &  : 

Rectangular  Base,  Rod  and  Rings 

$0.55 

.75 

.96 

6695 

SUPPORTS,  RING  OR  RETORT,  with  HARCOURT  OPEN  SIDE  FILTER  RINGS. 

a 

b 

c 

Small 

Medium 

Large 

No.  of  Rings 

2 

3 

4 

Diameter  of  Rings,  inches 

2  &  3 

2,  3  &  4 

2,  3,  4  & 

Tripod  Base,  Rod  and  Rings 

$0.52 

.70 

.90 

6697 

SUPPORTS,  RING  OR  RETORT  with  RINGS. 

a 

b 

c 

Small 

Medium 

Large 

No.  of  Rings 

2 

3 

4 

Diameter  of  Rings,  inches 

2  &  3 

2,  3  &  4 

2,  3,  4  & 

Rectangular  Base,  Rod  and  Rings 

$0.55 

.75 

.96 

6699 

SUPPORTS,  RING  OR  RETORT  WITH 

RINGS. 

a 

b 

c 

Small 

Medium 

Large 

No.  of  Rings 

2 

3 

4 

Diameter  of  Rings 

2  &  3 

2,  3  &  4 

2,  3,  4  & 

Tripod  Base,  Rod  and  Rings 

$0.52 

.70 

.90 

6701  THE  HARCOURT  LECTURE  TABLE  RING  STAND  AND  ATTACHMENTS. 

Consists  of  extra  large  Ring  Stand  with  4  Clamp  Holders,  Universal  Clamp  No.  4000,  Condenser  Clamp 
No.  4006,  Quick  Acting  Condenser  Clamp  No.  4013,  3  Harcourt  Open  Side  Rings,  2,  3  and  4-inch, 

Nos.  6460a  to  6460c,  2  Harcourt  Open  Side  Extension  Rings,  3  and  4-inch,  Nos.  6466b  and  6466c, 
and  Platform  Support.  Complete  Outfit . V . $4.35 


486 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6710 


No.  6711 


No.  6713 


No.  6716 


No.  6719 


No.  6724 


No.  6722 


No.  6720 


No.  6726 


TEST  TUBE  SUPPORTS.  Our  test  tube  supports  have  this  distinctive  feature,  —  they  will  hold 
tubes  one  inch  in  diameter. 


6710 

6711 
6713 

6716 

6717 
6719 


6720 

6722 

6724 

6726 

6727 
6736 


SUPPORT,  TEST  TUBE,  for  4  tubes,  with  4  drying  pins . $0.22 

- ,  for  6  tubes  with  6  drying  pins . .  .  .26 

SUPPORT,  TEST  TUBE,  for  12  tubes  with  12  drying  pins;  10  holes  are  1%e-inch  diameter,  2  holes  1^6 

inches  diameter,  with  drain  groove .  .42 

SUPPORT,  TEST  TUBE,  for  13  tubes  with  drying  pins .  .40 

SUPPORT,  TEST  TUBE,  for  25  tubes,  with  drying  pins .  .66 

SUPPORT,  KNOCKED  DOWN  TEST  TUBE.  This  support  occupies  a  very  small  compass  when 
packed  for  shipment.  It  is  very  readily  assembled,  offering  a  substantial  support.  For  sixteen  tubes 
with  drying  pins .  .60 

— — ,  same  as  above,  for  25  tubes,  with  drying  pins . 86 

SUPPORT,  TEST  TUBE  AND  FUNNEL,  after  Irish  for  8  tubes;  with  drying  pins;  two  adjustable 

funnel  supports .  .76 


SUPPORT,  TEST  TUBE,  WIRE,  galvanized  iron 
wire  rack  for  36  test  tubes . 

SUPPORT,  TEST  TUBE,  for  drying  tubes,  with  50 
drying  pins . 

- ,  with  25  drying  pins . 

SYRINGE,  HYPERDERMIC,  1  to  26  minims.  The 

distinctive  feature  of  this  syringe  is  that  the  bar¬ 
rel  is  ground  to  fit  the  metal  parts  and  the  syringe 
may  be  dissembled  for  cleaning.  With  two  steel 
needles  in  pasteboard  box . 


1.26  No.  6736 


CHEMISTRY  AND  BIOLOGY 


487 


Nos.  6795a-h 


No.  6800 


6802 


No.  6804 


No.  6806 


5642 

6795 

6798 

6800 

6802 

6804 


TABLES,  LOGARITHM,  a  heavy  board  card,  X  9 Y%  inches,  with  four  place  tables  of  logariths 
and  antilogariths,  with  table  of  atomic  weights,  also  Factors  for  Analysis.  Computed  by  Dr.  Hu¬ 
bert  G.  Shaw.  This  card  is  of  convenient  size  for  students’  use  in  the  laboratory.  Used  extensively 

and  for  years  at  the  Massachusetts  Institute  of  Technology . Each 

TEST  GLASSES,  on  foot,  clear  colorless  glass.  a  b 

Capacity,  ounces  2  4 

Each  $0.40  .45 

TEST  TUBES,  colorless  glass  tubes  of  special  glass,  resistant  to  changes  in  temperature. 

a  b  c  d  e  f  g 

Length,  inches  4  4  5  5  6  6  6 

Diameter,  inches  K  5A  Yt  %  fs  %  1 

Per  Gross  $1.90  2.10  2.26  2.40  2.60  2.76  4.25 

TEST  TUBES,  FUSED  SILICA.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.)  These  test 
tubes  are  of  great  service  in  laboratory  work,  as  they  withstand  high  temperatures  and  can  be  cooled 
rapidly  without  breakage.  a  b  c  d  e  f 

Size,  inches  4XH  5XH  5  X  Y  6  X  %  6  X  M  7  X  V& 

Each  $0.85  1.00  1.20  1.45  1.75  2.26 

TEST  TUBES,  BOSTON  BOARD  OF  HEALTH,  without  flange,  heavy  wall,  5  inches  long  X  i^j-inch 

diameter . . Per  Gross  $3.70 

TEST  TUBES  WITH  SIDE  NECKS.  a  b  c 

Length,  inches  6  8  10 

Each  $0.10  .12  .30 

TEST  TUBES  ON  FOOT,  colorless  glass  tubes  on  pedestal  bases. 


$0.35 


h 

8 

1 

5.00 


Height,  inches 
Diameter,  inches 
Each 


a 

4 

Vi 

$0.06 


b 

5 

X 

.08 


c 

6 

H 

.10 


d 

8 

1 

.20 


6806  TEST  TUBES,  GRADUATED. 

a 

b 

c 

Capacity,  cc. 

10 

20 

30 

Graduated  to  cc. 

X 

X 

X 

Each 

$0.44 

.52 

.66 

6816  TEST  TUBE  BASKETS  for  sterilizing  in  bacteriological  work.  Each 

TEST  TUBE  BRUSHES.  See  BRUSHES,  TEST  TUBE,  Page  419. 
TEST  TUBE  CLAMPS.  See  CLAMPS,  TEST  TUBE,  Page  423. 
TEST  TUBE  RACKS.  See  SUPPORTS,  TEST  TUBE,  Page  486. 


$0.50 


pisssis::^ 

IniM 


No.  6815 


THERMIT  REACTION  APPARATUS 

When  the  thermit  is  ignited  in  one  spot,  the  combustion  so  started  continues  throughout  the  entire 
mass  without  supply  of  heat  or  power  from  the  outside  and  produces  superheated  liquid  steel 
and  superheated  liquid  slag,  attaining  a  temperature  of  about  4881°  F.  in  less  than  30  seconds. 

The  advantage  of  such  a  compound  in  iron  and  steel  welding  is  at  once  apparent. 

In  order  that  science  instructors  may  demonstarte  the  properties  of  such  a  compound,  we  offer  com¬ 
bination  equipments  for  showing  a  few  fundamental  experiments. 

6819A  Thermit  Welding  a  Small  Piece  of  Steel  to  a  Steel  Plate . Complete  outfit  $2.45 

6819B  Thermit  Burning  a  Hole  through  a  Steel  Plate . Complete  outfit  21.00 

6819C  Thermit  Welding  a  Large  Boss  to  a  Steel  Plate . Complete  outfit  22.25 

6819D  Thermit  Used  in  Pipe  Welding . Complete  outfit  35.00 

6820  THERMIT  COMBINATION  OUTFIT.  Includes  all  material  and  equipment  necessary  to  perform  all 

four  experiments  above  listed.  Shipping  weight  270  pounds . Complete  outfit  66.00 

6820A  THERMIT  COMBINATION  OUTFIT.  Includes  all  material  and  equipment  necessary  to  perform 

experiments  of  Nos.  6819A  to  6819C.  Shipping  weight  230  pounds . Complete  outfit  31.00 

6821  THERMIT,  black . Per  Pound  .50 

6822  IGNITING  MIXTURE  (8  ounces  smallest  quantity  sold) . Per  Pound  1.30 

THERMOMETERS.  See  Pages  213  to  216. 

THERMO-REGULATORS.  See  GAS  REGULATORS,  Page  446. 

6966  THISTLE  TUBES  a  b  '  c 

Length,  inches  10  12  15 

Each  $0.08  .12  .15 

6826  TIN  FOIL,  regular  thickness . Per  Pound  1.25 


488 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6834 


TONGS,  CRUCIBLE.  See  CRUCIBLE  TONGS. 
6830  TRAYS,  GLASS  (Photo  Trays),  crystal  glass. 


a 

b 

c 

Size,  inches 

4  X 

6 

SA  x  &A 

8 

x  io y2 

Each 

$0.22 

.27 

.66 

TRAYS,  FUSED  SILICA,  rectangular. 

(See  index, 

“Fused  Silica  Ware, 

”  for  characteristics.) 

a 

b 

c  d 

e 

f 

g 

h 

Length,  outside,  inches 

6A 

10  12  % 

14 

iSK 

16X 

16X 

Width,  outside,  inches 

33A 

2Vs 

7  6 

4% 

9y2 

HH 

1 3% 

Depth,  outside,  inches 

7A 

1 

Vi  IK 

1 

I'A 

1A 

IK 

Each 

$2.00 

2.26 

3.26  3.60 

3.60 

4.26 

6.76 

7.00 

Nos.  6840a-c 


6840 


TRIANGLES,  “PIPE  STEM,”  iron  wire,  covered  with  porcelain,  raised  centers. 


a 

b 

c 

Small 

Medium 

Large 

Length  of  side,  inside,  inches 

2A 

3 

3H 

Each 

$0.08 

.08 

.08 

TRIANGLES,  PLATINUM.  See  PLATINUM  WARE,  Page  473. 


No.  6842 


No.  6843 


6842  TRIANGLES,  FUSED  SILICA  (Silica  Tubes  on  Iron  Wire).  (See  index,  “Fused  Silica  Ware,”  for 

characteristics.)  Will  outwear  innumerable  pipe-stem  triangles. 

a  bcdefghi  jk 

Length,  inches  1 A  1%  2  2 X  2A  2 %  3  3A  3A  3 A  4 

Each  $0.13  .13  .13  .16  .16  .20  .20  .26  .26  .30  .30 

6843  TRIANGLES,  FUSED  SILICA  (All  Silica  Tubes).  (See  index,  “Fused  Silica  Ware,”  for  characteristics.) 

a  bcdefghi  j 

Length,  inches  1A  1%  2  2 A  2'A  2 %  3  3A  3A  3 % 

Each  $0.76  .76  .76  .90  .90  1.00  1.00  1.00  1.16  1.16  1.26 


M 


CHEMISTRY  AND  BIOLOGY 


489 


6850 

6852 


6865 


6860 


e 

10 

12 

.86 


Diameters  given  are  outside  meas- 


6862 


TRIPOD,  japanned  iron,  8  inches  high.  Inside  diameter  of  ring  3%  inches,  with  three  legs  ....  $0.28 

TRIPODS,  japanned  iron,  8  inches  high. 

a  bed 

Inside  diameter,  inches  3  6  8 

Outside  diameter,  inches  5  6  8  10 

Each  $0.35  .45  .66  .70 

TRIPODS,  CONCENTRIC  RINGS,  japanned  iron,  8  inches  high, 
urements  of  largest  ring. 

a  b  c  d  e 

No.  of  Rings  2  3  4  5_  6 

Diameter,  inches  5  6  8  10  12 

Set  $0.48  .64  .84  1.20  1.60 

TROUGHS,  PNEUMATIC,  heavy  gauge  metal,  each  size  with  sliding  shelf  and  overflow  tube. 

a  be 

Length,  inches  9  12  14^ 

Width,  inches  6x/i  9  8% 

Depth,  inches  3%  5  5 

Each  $1.30  1.60  2.20 

TROUGH,  PNEUMATIC,  of  porcelain .  1.16 


6868  TUBING,  FUSED  SILICA  COMBUSTION.  (See  index,  “Fused  Silica  Ware,”  for  characteristics.) 

Fused  Silica  Combustion  Tubes  are  largely  employed  in  electric  resistance  furnaces  for  the  determina¬ 
tion  of  carbon,  oxygen,  and  sulphur  in  iron,  steel  and  other  non-volatile  metals;  for  the  determina¬ 
tion  of  sulphur  in  pyrites  cinder,  and  for  the  determination  of  carbon,  hydrogen,  halogens  and  sul¬ 
phur  in  organic  compounds. 

The  superior  heat  and  chemical  resisting  properties  of  Fused  Silica  have  led  to  the  general  adoption 
of  tubes  of  this  material  to  replace  glass,  porcelain  and  platinum  in  combustion  work. 


6872 

6873 
6875 


a 

b 

c 

d 

e 

f 

g 

Bore,  mm. 

1-2 

3 

4-5 

6-7 

8 

9-10 

11 

Thickness  of  Wall,  mm. 

.5-3 

.5-2.5 

.5-2 

.5-2 

.5-2 

1-2 

1-2 

Price  per  Foot 

$0.25 

.45 

.76 

.90 

1.10 

1.60 

1.40 

Extra  Price  per  tube  for  Closed  End 

$0.10 

.15 

.20 

.20 

.20 

.25 

.25 

h 

i 

j 

k 

1 

m 

n 

Bore,  mm. 

12-13 

14 

15-16 

17-18 

19 

22 

25 

Thickness  of  Wall,  mm. 

1-2 

1-2.5 

1-2.5 

1-2.5 

1-3 

1-3 

1-3 

Price  per  Foot 

$1.60 

1.60 

1.76 

1.90 

2.10 

2.30 

2.50 

Extra  Price  per  Tube  for  Closed  End  $0.25 

.35 

.36 

.60 

.60 

.65 

.76 

TUBES,  ABSORPTION,  Bunsen’s,  graduated  to  180  millimeters . $0.75 


TUBES,  ABSORPTION,  Bunsen’s,  with  Bulb.  Graduated  to  170  millimeters  1.00 

TUBES,  ARSENIC,  hard  glass.  a  bed 

$0.06  .06  .06  .06 

.22 


Set  of  Four 


490 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


No.  6880 


No.  6920 


No.  6882 


No.  6900 


No.  6887  No.  6888 


No.  6902 


No.  6911 


6880 

6882 

6884 

6887 

6888 

6890 


6896 

6900 

6902 


TUBES,  CALCIUM  CHLORIDE,  U-Shape,  Plain.  a  b 

Size,  inches  3  X  %  4  X  % 

Each  $0.14  .16 

TUBE,  CALCIUM  CHLORIDE,  6  inches  long,  designed’to  lay  flat  on  the  table 

and  useful  type . 

TUBES,  CALCIUM  CHLORIDE,  U-SHAPE,  with  side  tubes. 

Size,  inches 
Each 

TUBES,  CALCIUM  CHLORIDE,  straight  with  one  bulb. 

Size,  inches 
Each 

TUBES,  CALCIUM  CHLORIDE,  straight  with  two  bulbs. 

Size,  inches 
Each 

TUBES,  CALCIUM  CHLORIDE,  Marchard’s.  a 
Size,  inches  4  X  % 

Each  $0.25 

TUBE,  CHLORINE,  after  Newell’s  “Descriptive  Chemistry”  (Experiment  23) 
TUBES,  CONNECTING,  BRASS,  for  reducing  from  Vie  to  %2  inch  .... 


5]X  % 

.18 

A  most 


d 

6XM 

.20 

convenient 


a 

b 

c 

4  X  M 

6  XlH 

8XM 

$0.26 

.32 

.60 

a 

b 

c 

4X  K 

6X% 

8  XH 

$0.10 

.14 

.16 

a 

b 

c 

Small 

Medium 

Large 

4  X  H 

6XH 

8  XH 

$0.10 

.16 

.18 

b 

6XH 

.33 

$0.48 


$0.77 

.16 


Diameter,  inch 

% 

X 

X 

Each 

$0.27 

.32 

.40 

6904 

TUBES,  CONNECTING,  BRASS,  Y  Shape. 

a 

b 

c 

Diameter,  inch 

% 

Vs 

X 

Each 

$0.27 

.32 

.40 

6906 

TUBES,  CONNECTING,  GLASS,  T  Shape. 

a 

b 

c 

d 

Diameter,  inch 

M 

% 

X 

X 

Each 

$0.08 

.10 

.13 

.16 

6908 

TUBES,  CONNECTING,  GLASS,  Y  Shape. 

a 

b 

c 

d 

Diameter,  inch 

x 

X 

X 

X 

Each 

$0.08 

.10 

.13 

.16 

6910 

TUBE,  CONNECTING,  LEAD,  Y  Shape,  Xi  inch 

6911 

TUBE,  CONNECTING,  WHITE  METAL,  Y  Shape,  for  V8-mch  rubber  tubing 

6920 

TUBES,  CULTURE,  of  medium  heavy  glass,  round  bottom, 

no  lip. 

a 

b 

c 

Size,  inches 

4  xy2 

5  xYi 

6X3A 

Per  Dozen 

$0.24 

.32 

.40 

$0.22 

.26 


TUBES,  DISTILLING,  see  DISTILLING  TUBES,  Page  436. 


CHEMISTRY  AND  BIOLOGY 


491 


No.  6925 


No.  6923 


Nos.  6935a-c 


No.  6966  No.  6962  No.  6960  No.  6960 


6923  TUBE,  FERMENTATION,  with  graduated  test  tube.  (Dr.  Einhorn’s  Saccharometer.) 

With  directions  . $0.75 

6926  TUBES,  FERMENTATION,  ungraduated,  on  foot. 


6620 


Length,  inches 
Diameter,  inch 
Each 


Diameter  of  Top,  mm. 

Each 

TUBES,  GAS,  for  collecting  gases  over  mercury. 
Capacity,  cc. 

Subdivided,  cc. 

Each 

6935  TUBES,  IGNITION,  ordinary  hard  glass. 
Length,  inches 
Diameter,  inch 
Each 


Length,  inches 
Diameter,  inch 
Each 

6945  TUBES,  NESSLER’S,  for  ammonia  tests  in  water  analyses;  of  colorless  glass. 

a  be 

Graduated,  cc.  50  100  50  &  100 

Each  $0.65  .80  .96 

6960  TUBE,  SAFETY,  thistle  top,  one  bulb  in  bend,  length  12  inches . $0.17 

6952  TUBE,  SAFETY,  thistle  top,  bend  in  stem.  Length  12  inches .  .22 

TUBES,  SPECIMEN.  See  VIALS,  Page  492. 

6965  TUBES,  THISTLE.  a  b  c 

Length,  inches  10  12  15 

Each  $0.08  .12  .15 

6960  TUBE,  VINEGAR,  Massachusetts  Board  of  Health,  for  determining  the  percentage  of  alcohol 


a 

b 

SH 

6  X 

X 

X 

$0.27 

.33 

:ms  ground  to  a  point. 

a 

b 

c 

25 

30 

35 

$0.24 

.56 

.64 

y.  a 

b 

50 

100 

X 

X 

$1.45 

1.80 

a 

b 

c 

4 

6 

8 

X 

X 

1 

$0.05 

.07 

.14 

glass,  best  for  generating  oxygen. 

a 

b 

c 

4 

6 

8 

X 

X 

1 

$0.12 

.16 

.32 

No.  5620b 


No.  6945 


$0.45 


Nos.  6970  and  6971 

6970  TUBING,  GLASS,  best  quality,  free  from  lead,  especially  adapted  for  glass  blowing  and  bending,  usual 

wall  for  chemical  laboratory  purposes.  The  following  sizes  are  carried  in  stock,  —  4,  5,  534,  6,  6J4.  7, 

8,  9,  10,  12,  15,  18,  20,  22,  and  25  millimeters  outside  diameters . Per  Pound  $0.54 

6971  TUBING,  GLASS,  same  as  above  in  quality,  but  larger  in  diameter.  The  following  sizes  are  carried 

in  stock,  —  30,  35  and  40  millimeters  outside  diameter . Per  Pound  .66 

Note.  —  In  ordering  Glass  Tubing,  always  specify  the  diameter  desired. 

6973  TUBING,  GLASS  CAPILLARY,  outside  diameter  6-7millimeters,  bore  1  and  IK  millimeters.  (In 

ordering  specify  bore  desired.) . . . Per  Pound  .76 

6976  TUBING,  GLASS  BAROMETER,  outside  diameter  8-9  millimeters,  bore  3  millimeters  Per  Pound  .76 


492 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


Nos.  6977  to  6979 


6977  TUBING,  ALUNDUM  (See  Index,  “Alundum  Ware,”  for  characteristics).  Length  12  inches. 


6978 


6979 


a 

b 

c 

d 

Bore,  inch 

34 

H 

1 

Wall,  inch 

Vs 

Vs 

Vs 

Vs 

Each 

$2.26 

2.25 

2.35 

2.60 

— ,  length  18  inches. 

a 

b 

c 

d 

Bore,  inch 

% 

V* 

1 

Wall,  inch 

Vs 

Vs 

Vs 

Vs 

Each 

$3.60 

3.60 

3.76 

3.90 

— ,  length  24  inches. 

a 

b 

c 

d 

Bore,  inch 

Vi 

H 

1 

Thickness,  inch 

Vs 

Vs 

Vs 

Vs 

Each 

$6.00 

5.00 

5.20 

5.35 

Note.  —  Alundum  Tubes  up  to  10-inch  bore  by  )4-inch  wall  can  be  obtained.  Prices  on  application. 
A  charge  of  10  per  cent,  additional  to  above  prices  will  be  made  for  closing  one  end  of  the  tube. 


6982 


TUBING,  GLASS  COMBUSTION,  of  hard  glass,  melting  point  800°  C.  Outside  diameter  8,  10,  13,  19 
and  25  millimeters.  (In  ordering  specify  sizes  desired) . Per  Pound 


$1.35 


6984 


6990 


TUBING,  PORCELAIN  COMBUSTION.  Glazed  inside  and  outside.  Will  stand  a  temperature  of 
1800  degrees  Fahrenheit  and  is  practically  gas  tight.  In  24-inch  lengths. 

a  b  c  d  e  f 

Diameter,  inch  ZA  %  %  1  1  V  1)4 

Per  length  $1.80  2.20  2.50  3.00  3.60  4.20 

TUkERIC  PAPER . Per  Sheet 

Per  Quire 


$0.04 

.66 


No.  7076 


Nos.  7080a-f 


7075 


VASCULUM  OR  COLLECTING  CASE,  of  metal,  with  leather  shoulder  straps.  Size  18  X  6)4  X  4)4 
inches  . 


7080 


Capacity,  drams 
Height,  mm. 
Diameter,  mm. 
Per  Dozen 


tit  wall, 

for  use  with  corks. 

a 

b 

c 

d 

e 

f 

1 

2 

3 

4 

6 

8 

45 

55 

60 

65 

70 

75 

15 

17 

19 

21 

23 

25 

$0.12 

.15 

.18 

.20 

.30 

.40 

$1.75 


CHEMISTRY  AND  BIOLOGY 


493 


7085 

7090 


7095 


7100 


VISCOSIMETER,  SCOTT’S,  for  determining  the  viscosity  of  oils,  etc. 
paring  very  favorably  with  those  of  much  higher  price . 


A  reliable  instrument  com- 

. $14.25 


VISES  for  laboratory  use, 

with  hardened  anvil  and  jaws. 

a 

b 

Length  of  Jaw,  inches 

m 

2 

Jaws  open,  inches 

2 

2V2 

Dimensions  of  Anvil 

H  X  1 

1  x  1H 

Each 

$0.66 

.95 

VOLUMETRIC  FLASK.  See  FLASKS,  VOLUMETRIC. 
WARMING  TABLE.  See  Page  466. 

WASHING  BOTTLES.  See  BOTTLES,  Page  418. 


WATCH  GLASSES,  thin  and  well  annealed. 

a  be 

Diameter,  inches  1  2 

Per  Dozen  $0.18  .20  .26 


d  e 

2  a  3 

.48  .54 


f  g 

3'A  4 

.76  .88 


h  i 

5  6 

1.50  2.60 


WATCH  GLASSES,  SYRACUSE,  designed  so  that  one  may  be  placed  above  another;  outside  diam¬ 
eter  70  mm.,  inside  diameter  53  mm . Per  Dozen  $0.60 


7110  WATCH  SPRINGS 


Per  Dozen  .20 


7116  WAX,  SEALING,  in  sticks 


Per  Pound  .44 


7120  WAX  TAPERS . Per  Box  $0.10 

WEIGHTS.  See  pages  58  to  63. 

WICKS  for  Alcohol  Lamps.  See  Page  462. 

WIRE,  all  kinds.  See  pages  311  to  313. 

WIRE  GAUZE.  See  page  446. 

60-80  WATER  HEATER  WITH  BURNER.  Will  heat  water  to 
boiling  point  in  three  minutes.  Consists  of  a  solid  flame 
burner  on  which  is  placed  the  water  heater.  This  heater 
consists  of  a  coil  of  copper  tubing  encased  in  a  finished 
metal  casting.  The  cold  water  enters  this  heating  tube 
and  by  regulating  flow  of  water  and  height  of  flame,  the 
issuing  water  may  be  obtained  either  boiling,  hot,  warm 
or  cold.  Total  height  9  inches.  With  Burner,  complete  $9.50 

60-81  WATER  HEATER  only,  same  as  above  but  without  burner  6.60 

WATER  HEATER,  ELECTRIC.  See  ELECTRIC  APPLI¬ 
ANCES,  Page  436. 


No.  60-80 


494 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


ALUNDUM  WARE 

Alundum  is  fused  aluminum  oxide.  When  bonded  with  ceramic  materials  and  given  proper  heat  treatment, 
refractory  articles  can  be  obtained  that  have  many  desirable  properties.  Pure  alundum,  which  is  more  than  99  per 
cent,  aluminum  oxide,  melts  at  2050°  C.  and  the  bonded  shapes  at  temperatures  somewhat  less  than  this  depending 
on  the  character  of  the  mixtures. 

Alundum  is  a  very  inert  substance  and  the  bonded  articles  are  not  readily  attacked  by  chemically  active  solu¬ 
tions. 

Alundum  is  a  poor  conductor  of  electricity  and  is,  therefore,  particularly  valuable  in  electrical  constructions. 

PROPERTIES. 

Coefficient  of  Expansion  —  0.0000071  per  degree  C. 

Specific  Electrical  Resistance. 

130  megohms  at  528°  Centigrade 


16 

<C 

“  730° 

U 

5.3 

U 

“  892° 

a 

1.8 

it 

“  1020° 

tt 

Porosity:  —  Three  mixtures  may  be  obtained,  —  36  .9  per  cent.,  40.7  per  cent,  and  47.4  per  cent.  We  carry  in 
stock  mixtures  of  40.7  per  cent,  porosity. 

Filter  Cones  have  special  mixtures  and  may  be  specified  as  dense,  medium  or  coarse.  We  carry  in  stock  a  mix¬ 
ture  giving  the  medium  porosity. 

All  Filter  Discs  have  a  porosity  of  43.9  per  cent. 

Alundum  articles  listed  in  this  catalogue  are  carried  in  stock  for  immediate  shipment.  Muffles,  other  articles, 
and  special  pieces  can  be  obtained.  We  should  be  most  pleased  to  correspond  regarding  special  needs. 


“PYREX”  GLASSWARE 

“PYREX”  Glassware  was  recently  developed  in  this  country  and  holds  promise  of  still  greater  extensive  use 
than  at  present. 

1.  It  contains  no  heavy  metals  nor  metals  of  the  magnesium  —  lime  —  zinc  group. 

2.  Under  numerous  tests  for  determining  stability  in  comparison  with  best  other  glasses  “Pyrex”  Glassware 

has  proved  greatly  superior. 

3.  “Pyrex”  Glassware  does  not  commence  to  soften  below  800°  C.  and  a  rod  heated  to  300°  C.  and  then 

plunged  into  cold  water  will  not  break. 

4.  Its  chief  characteristic  is  that  of  thick  walls,  a  construction  made  possible  by  the  very  low  expansion 

coefficient  of  0.0000032  (porcelain  has  an  expansion  coefficient  of  0.0000036).  This  characteristic  greatly 
increases  the  durability  of  the  vessels  without  diminishing  the  resistance  to  sudden  heating  and  cooling. 

Our  stock  of  “PYREX”  Glassware  as  listed  through  this  catalogue  is  complete.  We  offer  it  as  resistance  ware 
well  comparable  with  Jena  Glassware  that  cannot  now  be  obtained. 


FUSED  SILICA  WARE 

The  unusual  properties  of  Pure  Fused  Silica  Ware  make  it  suitable  for  most  analyses  where  platinum  has  here¬ 
tofore  been  necessary.  These  properties  are: 

1.  Its  melting  point  is  above  1500°  C. 

2.  Its  coefficient  of  expansion  is  extremely  small  being  .00000059,  which  is  about  VL7th  that  of  glass.  Crucibles 

or  other  dishes  may  be  heated  to  red  heat  and  then  plunged  into  cold  water  without  cracking  or  breaking. 

3.  It  is  not  attacked  by  acids. 

4.  It  is  absolutely  constant  in  weight. 

5.  It  is  insoluble  in  water. 

On  account  of  the  increased  cost  of  platinum  the  various  laboratory  vessels  and  utensils  listed  in  this  catalogue 
may  profitably  receive  the  careful  consideration  of  every  chemist. 


CHEMISTRY  AND  BIOLOGY 


495 


ROYAL  WORCESTER  PORCELAIN  WARE 


Royal  Worcester  Porcelain  Ware  has  been  most  carefully  tested  to  ascertain  its  suitability  for  laboratory  use 
in  comparison  with  similar  ware  so  readily  obtained  before  the  European  War. 


The  National  Physical  Laboratory  of  Teddington,  England,  has  directed  tests  to  ascertain 

1.  The  Effect  of  Chemical  Reagents. 

2.  The  Behavior  of  the  Glaze  at  High  Temperatures. 

3.  Constancy  of  the  Weight  of  the  Ware. 

4.  Resistance  to  Sudden  Changes  of  Temperature. 

1.  THE  EFFECT  OF  CHEMICAL  REAGENTS. 

(a)  Strong  Sulphuric  Acid. 

After  a  four-hour  test  the  acid  acting  on  209  square  centimeters  a  dish  gained  0.0016  gram, —  (a  gain 
of  0.0008  gram  per  100  square  centimeters. 

(b)  10  per  cent.  Solution  Caustic  Soda  at  90°-100°  C.  (Concentration  of  solution  by  evaporation  prevented 
by  conducting  the  experiment  in  a  closed  oven.) 

After  a  four-hour  test,  the  caustic  soda  solution  acting  on  209  square  centimeters,  a  dish  lost  in  weight 
-0.0308  gram,  —  a  loss  of  0.0147  gram  per  100  square  centimeters. 

(c)  10  per  cent.  Solution  Sodium  Carbonate  at  90°-100°  C.  (Concentration  of  the  solution  by  evaporation 
prevented  by  conducting  the  experiment  in  a  closed  oven.) 

After  a  four-hour  test,  the  sodium  carbonate  acting  on  209  square  centimeters,  a  dish  lost  in  weight 
-0.0018  gram,  —  a  loss  of  0.0009  gram  per  100  square  centimeters. 

2.  BEHAVIOR  OF  THE  GLAZE  AT  HIGH  TEMPERATURES. 

(a)  A  few  broken  pieces  of  Royal  Worcester  Porcelain  were  placed  in  a  Royal  Worcester  Porcelain  Dish 
and  heated  for  four  hours  in  a  large  gas  muffle  the  temperature  of  which  was  kept  constant  at  1000°  C. 

Fragments  of  porcelain  adhered  to  the  dish  but  were  readily  removed  by  slight  pressure  of  the  fingers, 
but  the  glaze  of  the  dish  was  but  slightly  affected.  The  dish  was  not  at  all  discolored  and  the  brightness  of 
the  glaze  was  not  appreciably  dimmed. 

3.  CONSTANCY  OF  THE  WEIGHT. 

(a)  A  dish  weighing  22  grams  was  first  gently  heated,  cooled  and  weighed.  It  was  then  heated  for  one  and 
one-half  hours  in  a  muffle  at  a  temperature  of  850°  C. 

After  cooling  the  dish  showed  a  loss  of  but  0.0002  gram. 

4.  RESISTANCE  TO  SUDDEN  CHANGES  OF  TEMPERATURE. 

*  • 

(a)  A  dish  was  first  filled  with  wax  which  was  melted  and  heated  gradually  to  a  temperature  of  160°  C.  It 
was  then  allowed  to  cool  to  150°  C.  to  secure  that  the  temperature  of  the  dish  was  equal  to  that  of  the  wax. 

The  dish,  when  plunged  with  contents  into  water  at  15°,  remained  unbroken. 

This  treatment  was  continued  in  a  similar  way  at  successively  higher  temperatures  up  to  230°  C.,  the 
dish  remaining  intact. 

(b)  A  dish  was  heated  in  a  muffle  at  a  temperature  of  850°  C.  It  was  then  removed  with  a  thick  pair  of  cold 
iron  tongs  and  placed  on  a  cold  stone  bench  to  cool. 

.  No  cracking  or  chipping  even  of  the  glaze  was  observed. 

As  a  result  of  these  tests,  we  ordered  a  sample  line  of  this  ware  and  have  had  it  tested  by  men  of  the 
highest  reputation  in  this  country.  Their  reports  enable  us  to  recommend  this  ware,  confident  that  it  in  every 
way  meets  the  most  exacting  demands  of  Chemists. 


496 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


NATIONAL  LOOSE-LEAF  NOTE-BOOKS 

BIOLOGY  —  CHEMISTRY 

By  Arthur  S.  Dewing,  Ph.D. 

The  effort  has  been  to  prepare  these  laboratory  instructions  in  a  manner  to  give  students  only  such  assistance 
as  will  enable  them  to  observe  and  think  for  themselves.  The  author  has  avoided  most  carefully  the  “Verification 
Method”  of  teaching  science  by  which  the  student  is  told  exactly  what  he  is  to  find  or  what  conclusion  to  draw.  The 
pupil  is  guided  right  to  follow  an  individual  channel  in  constructive  observation  and  from  a  suggested  sequence  of 
thought  learns  to  observe  accurately  and  think  clearly. 

The  Loose-leaf  System  has  long  been  recognized  as  one  that  affords  the  greatest  latitude  for  choice  and  one  that 
is  best  adapted  to  individual  requirements.  A  teacher  is  enabled  to  select  from  a  series  of  experiments  greater  than 
required,  the  experiments  adapted  particularly  to  individual  conditions.  One  may  select  a  series  adapted  to  meet 
State  requirements,  local  educational  requirements,  etc.,  etc.  We  have  endeavored  to  keep  in  file  courses  of  labora¬ 
tory  instruction  satisfactorily  meeting  in  actual  use  the  many  requirements.  We  should  be  pleased,  therefore,  to 
send,  upon  request,  a  note-book  containing  a  series  of  direction  sheets  in  Chemistry,  Biology  or  Physics  (See  page 
27)  outlining  a  course  found  entirely  adequate  in  meeting  similar  requirements.  Such  service  is  entirely  gratis. 

NATIONAL  BIOLOGY  DIRECTION  SHEETS 

This  series  covers  Botany,  Zoology  and  Physiology,  118  sheets.  A  number  of  these  direction  sheets  are  in 
the  nature  of  introductory  exercises  concerning  the  general  nature  of  organisms  and  their  simple  chemical  processes 
and  they  should,  when  possible,  precede  the  work  in  any  of  the  special  exercises.  Larger  amounts  of  matter  are 
given  in  every  case  than  can  ordinarily  be  undertaken,  the  author  believing  that  a  variety  of  conditions  requires  a 
variety  of  methods  and  subjects. 

A  FEW  NOTES  AND  COMMENTS 

Wallace,  Idaho,  Independent  School  District  No.  8. 

“I  believe  the  use  of  your  books  will  do  more  to  standardize  science  work  than  anything  else;  at  the  same  time  they  allow  for  a  teach¬ 
er's  preference  and  originality  by  providing  a  choice  of  sheets.  As  I  am  myself  using  the  Biology  Set,  I  shall  make  quite  a  point  of  that 
to  illustrate  the  system.” 

Louisville,  Ky.,  High  School. 

“I  find  the  Note-Book  very  interesting  and  full  of  practical  usefulness.” 

Ashburnham,  Mass.,  Cushing  Academy. 

“I  am  using  the  Note-Book  in  my  class  and  find  it  most  satisfactory." 

Webster  Groves,  Mo.,  High  School. 

"I  have  been  using  your  National  Note-Books  in  Botany  and  Physics  this  year,  and  wish  to  express  to  you  my  complete  satisfac¬ 
tion  in  regard  to  same.  This  has  been  my  idea  of  a  note-book  for  many  years,  but  have  never  before  found  one  so  well  selected  and 
arranged,  so  reasonable  in  price  and  so  neatly  put  up  and  constructed,  as  the  ones  secured  from  you.” 

"They  are  the  best  I  know  of  and  shall  not  only  use  them  myself,  but  expect  to  speak  of  them  to  all  who  teach  science,  with 
whom  I  come  in  contact.” 

Dryden,  N.  Y.,  High  School. 

“The  sheets  of  the  National  Biology  Note-Book  are  in  use  in  this  school  and  I  am  glad  to  say  that  they  are  a  great  help  in  that 
subject.  We  also  use  the  National  Physics  Note-Book  and  find  it  very  practicable.  I  thank  you  for  your  interest  and  your  attempt 
to  supply  so  many  good  things  that  schools  want." 

Eugene,  Ore.,  University  of  Oregon. 

"I  have  examined  with  interest  the  Loose-Leaf  Note-Book  for  Biology  which  you  sent  us.  It  seems  to  be  an  excellent  plan.  There 
has  been  a  very  wise  selection  of  the  essentials.  I  shall  take  pleasure  in  recommending  this  to  teachers.” 

NATIONAL  CHEMISTRY  DIRECTION  SHEETS 

The  National  Chemistry  Direction  Sheets  were  prepared  to  meet  several  demands.  In  the  first  place  the  ex¬ 
periments,  exercises,  and  descriptive  matter,  when  taken  together,  and  in  the  order  indicated  by  the  Index,  supply 
a  clearly  defined  method  for  teaching  Chemistry.  Its  spirit  is  to  develop  the  powers  of  observation  and  inference. 
The  series  covers  148  sheets  from  which  number  the  teacher  is  enabled  to  select  a  course  adapted  to  individual  need. 

A  FEW  NOTES  AND  COMMENTS 
Boston,  Mass.,  Noble  &  Greenough’s  Classical  School. 

“The  work  done  in  my  Chemistry  class  this  year  has  been  much  simplified  by  the  use  of  your  Chemistry  Loose-Leaf  Notes. 
With  a  proper  amount  of  selection  of  the  notes  I  find  I  have  been  able  to  accomplish  the  laboratory  work  in  less  time  than  usual  and,  I 
think,  with  more  satisfactory  results." 

Fitchburg,  Mass.,  High  School. 

“I  believe  that  by  a  proper  use  of  the  Notes,  a  good  course  could  be  given  in  any  school,  using  specially  adapted  experiments  and 
your  notes  in  place  of  any  regular  text." 

Albany,  N.  Y.,  State  Normal  College. 

"You  are  at  liberty  to  use  anything  that  I  have  written  commendatory  of  the  Loose-Leaf  Note-Books.  I  think  they  are  the  ideal 
plan  for  teaching  Chemistry  in  the  laboratory,  and  when  accompanied  by  efficient  supervision  of  the  students  at  work,  by  study  from 
a  well-digested  text-book,  and  by  discussion  in  the  classroom,  and  all  summed  up  by  the  teacher  in  a  weekly  lecture  with  demonstrative 
experiments,  the  course  could  not,  in  my  opinion,  be  surpassed." 

Cincinnati,  Ohio,  St.  Xavier  College. 

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exercises  are  very  suggestive,  and  stimulate  to  thought  and  attention.  They  are  well  chosen,  I  believe,  to  develop  a  mental  attitude 
of  scientific  inquiry  in  the  pupil." 

Little  Rock,  Ark.,  Arkansas  Military  Academy. 

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future_ orders  from  our  school.” 

Canon  City,  Colo.,  High  School. 

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Barboursville,  Ky.,  Union  College. 

“We  are  using  both  your  Physics  and  Chemistry  Note-Books  in  our  work  at  Union  College  and  you  will  doubtless  be  gratified  to 
know  that  we  are  highly  pleased  with  them.  They  are  thoroughly  practical  for  laboratory  use.” 

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CHEMISTRY  AND  BIOLOGY 


497 


LIQUID  STAINS  AND  REAGENTS 


Aniline  Water  . 

Bismarck  Brown,  aqueous  solution  (Weigert) . 

Bismarck  Brown,  alcoholic  solution . 

Carmine  Alcohol  (P.  Mayer) . 

Carmine  Alum  (Grenacher) . 

Carmine  Ammonia  (Gerlach’s) . 

Carmine  Borax  (Grenacher) . 

Carbol  Fuchsin  (Ziehl’s) . 

Carbol  Gentian  Violet  (Oppenheim  Sach’s) . 

Carmalum  (P.  Mayer) . 

Chenzinsky  —  Plehn’s  Stain  (Eosin  and  Methylene  Blue)  . 

Congo  Red  (indicator) . 

Corallin  Soda  Solution  (Strassburger) . 

Eosin  in  Ethylic  Alcohol . 

Eosin  in  Methylic  Alcohol  .  .  . . 

Ehrlich’s  Acid  Haematoxylin . 

Ehrlich’s  Diazo  Reaction  No.  1 . 

Ehrlich’s  Diazo  Reaction  No.  2 . 

Esbach’s  Reagent  .  • . .  .  . 

Fehling’s  Reagent  No.  1  and  No.  2  (Copper  and  Alkali)  .  . 

Fuchsin  basic  in  Ethylic  Alcohol . 

Fuchsin  Acid  in  Ethylic  Alcohol . 

Fuchsin,  basic  aqueous  solution . 

Gentian  Violet  Amline  Water  (Gram’s) . 

Gabbett’s  Stain  (Methylene  Blue  Sulphuric  Acid)  .  .  .  . 

Gabbett’s  Stain  (Carbol  Fuchsin) . 

Giemsa  Stain  for  Malaria . .  ...  . 

Giemsa  Stain  for  Spirochaeta . 

Gunzberg  Solution . 

Haematoxylin  (Delafield’s) . 

Haematoxylin  Iron  (Heidenhain’s) . 

Haematoxylin  Lithium  Carbonate,  one  solution  (Weigert)  .  . 

Hayem’s  Solution  for  Blood . 

Haines’  Solution  for  Sugar  in  Urine . 

Jenner  Stain . 

Leischman  Stain  . . . 

Lugol’s  or  Gram’s  Iodine  Solution . 

Methylene  Blue  Alkaline  (Loeffler) . 

Methylene  Blue  Borax  (Unna) . 

Methylene  Blue,  aqueous  solution . 

Methylene  Blue,  Ethylic  Alcohol  Solution . 

Methylene  Blue  Polychrome  (Unna) . 

Meyer’s  Albumen  Fixative . 

Obermeyer’s  Reagent . 

Purdy’s  Reagent  (for  sugar)  . 

Piero  Carmin  (Ranvier) . 

Phenolphthalein  (Indicator)  . 

Uffelman’s  Reagent  (Milk  Sugar  in  Stomach  Contents)  .  .  . 

Toepf^r  Solution . 

Toison  Solution . 

Weigert  Stain  (Borax  Potassium  Cyanide  Solution)  .  .  .  . 

Weigert  Stain  (Fuchsin  Solution) . 

Wright  Stain  (Blood  Stain) . 


DRY  STAINS 


Azur 1  . 

Azur  11  .  .  .  . 

Azur  1 1  Eosine  . 
Congo  Red  ..  .  . 

Eosine . 

Fuchsin  Basic 
Gentian  Violet  .  . 
Malachite  Green 
Methylene  Blue  . 
Methyl  Violet  .  . 
Primuline  .  .  . 


Per 

Per 

Per 

25  cc. 

100  cc. 

Pound 

$0.30 

$0.50 

.25 

.60 

.35 

.76 

.56 

1.35 

.60 

1.25 

.35 

.76 

.45 

1.10 

.60 

1.25 

.50 

1.25 

.36 

.75 

.50 

.95 

.35 

.90 

.60 

1.60 

.55 

1.20 

.76 

1.66 

1.00 

1.80 

.60 

1.60 

.60 

1.60 

.60 

.55 

1.00 

.55 

1.00 

.55 

1.00 

.55 

1.00 

.65 

1.00 

.60 

1.00 

.50 

1.25 

.60 

1.35 

1.25 

4.00 

2.00 

6.00 

.60 

1.60 

.60 

1.35 

.60 

1.35 

.60 

.75 

$2.00 

.55 

1.66 

.65 

1.80 

.50 

.90 

.60 

1.60 

.60 

1.05 

.50 

.90 

.90 

1.95 

.90 

1.80 

.60 

.60 

.90 

2.00 

.60 

1.65 

.76 

.60 

1.60 

.50 

1.00 

.60 

1.00 

.76 

1.60 

.60 

1.20 

.60 

1.95 

Per 

Per 

Per 

Gram 

$4.50 

10  Grams 

Ounce 

3.00 

3.76 

$2.60 

$4.00 

2.60 

4.00 

2.60 

4.00 

4.00 

2.60 

4.00 

2.50 

4.00 

2.50 

4.00 

2.50 

4.00 

498 


L.  E.  KNOTT  APPARATUS  CO.,  BOSTON 


INDEX 


A 


PAGE 


PAGE 


PAGE 


Abbe  Camera  Lucidae . 460 

Abbe  Condensers  . 459 

Absorption  Apparatus,  Hydrogen, 

Hall  . 403 

Absorption  Screen  . 206 

Absorption  Troughs . 272 

Absorption  Tubes . 489 

Acceleration  Apparatus  ...  101-106 

Acceleration  Apparatus,  Inclined 

Wire  . 103 

Acetylene  Gas  Bunsen  Burner  .  .  200 

Achromatic  Lenses . 259 

Achromatic  Objectives  ....  458,  459 
Achromatic  Prisms  .  .  261,  262,  271 

Acid  Bottle  . 415 

Acid  Brush . 419 

Acid  Burettes  . 468 

Acid  Dish . 430 

Acid  Funnel  . 468 

Acid  Measures  . 468 

Acid  Pipettes . 468 

Acid  Pump . 474 

Acme  Water  Still . 210 

Acoustic  Reaction  Wheel  ....  197 

Action  and  Reaction  Apparatus  .  87-90 

Action  and  Reaction  Apparatus,  Hall  141 
Action  and  Reaction  Strip,  Hall  141 

Adhesion  Disc  .  73 

Adjustable  Resonator  and  Bell  .  .  197 

Adjustable  Spark  Gaps  . 383 

Agateware  Casseroles  . 421 

Agateware  Dishes . 430 

Air  Condensers . 388 

Air  Impulse  Attachment .  82 

Air  Pump  Plates  . 151 

Air  Pumps . 149-153 

Air  Storage  Tanks . 153 

Air  Testers . 406 

Air  Thermometer  Bulb . 218 

Air  Thermometers  . 217,  218 

Alcohol  Burners  . 201 

Alcohol  Lamps  . 452 

Alcoholometers  . 448 

Alcohol,  Solid  . 406 

Alcohol  Stoves  . 202 

Alkaline  Tablets,  Farrington’s  .  .  468 

Alternating  Current  Demonstration 

Apparatus .  376,  399 

Alternating  Current  Meters  ....  353 

Aluminum  Beakers  . 413 

Aluminum  Block  . 129 

Aluminum  Cylinder . 129 

Aluminum  Leaf . 293 

Aluminum  Leaf  Cutting  Apparatus  293 

Aluminum  Milk  Dishes  . 432 

Aluminum  Shot . 229 

Alundum . 406 

Alundum  Capsules . 421 

Alundum  Cement . 406 

Alundum  Combustion  Boats  .  .  .  425 

Alundum  Combustion  Boat  Shields  425 

Alundum  Crucibles . 427 

Alundum  Extraction  Thimbles  .  .  436 

Alundum  Filter  Cones . 437 

Alundum  Filter  Crucible . 428 

Alundum  Filter  Dishes . 432 

Alundum  Incinerating  Dishes  .  .  .  432 

Alundum  Pyrometer  Tubes  ....  475 

Alundum  Tubing  . 492 

Alundum  Ware . 494 

Amber  Specimen  . 289 

Amici’s  Direct  Vision  Prisms  .  .  .  261 

Ammeters  .  350-353 

Ammonium  Hydroxide  . 403 

Ampere’s  Frame . 328 

Ampere’s  Law  Apparatus  .  .  .  327,  328 

Ampere’s  Law  Stand  . 327 

Amyl-Acetate . 246 

Analytical  Balances . 46^18 

Andrews  Plate  Base .  12 

Anemometers . 168 

Aneroid  Barometers . 161,  162 

Anglegraph .  43 

Animal  Parchment  . 156 

Anode,  Platinum  . 473 


Anodes,  Copper,  Nickel,  Silver  .  .  403 


Antimony  Rubber  Stoppers  .  .  .  478 

Antimony  Rubber  Tubing  ....  477 

Anvil  Vise  Attachment,  T-Beam  .  26 

Anvil  Vise,  T-Beam .  26 

Apparatus  A  . 203 

Applied  Physics  Apparatus  .  121-127 

Apron  . 406 

Aquaria  . 406 

Aquaria  Jars . 406 

Aquarium  Table . 406 

Aquarium  Tank  . 406 

Arago’s  Magnetic  Rotation  Appa¬ 
ratus  .  83 

Archimedes’  Principle  . 128 

Arch  Model . 126 

Arc  Lamp,  Demonstration  .  .  159,  404 

Armatures,  Iron,  T.  &  H . 279 

Arsenic  Tubes .  407,  489 

Artificial  Light  Circuit . 312 

Asbestos . 407 

Asbestos  Boards . 407 

Asbestos  Chimney . 240 

Asbestos  Gauze . 446 

Asbestos  Wool . 407 

Aspirator  Bottle . 415 

Aspirators .  153,  407 

Astatic  Galvanometer . 334 

Astatic  Needle . 285 

Astronomical  Telescope  Model  .  .  .  266 

Astronomical  Telescopes  .  .  .  264-266 

Atomic  Weight  Chart . 422 

Attachment,  Burette . 419 

Attachment  Clamps,  T-Beam  ...  26 

Attachments,  Burner . 420 

Atwood’s  Attachment  for  Accelera¬ 
tion  . 103 

Augur  Bits . 405 

Automatic  Microtomes  ....  464,  465 
Automatic  Overflow  Pipettes  .  .  .  472 

Automatic  Pipettes  . 468 

Automatic  Zero  Burette . 419 

Auxanometers . 408 

Avoirdupois  Weights .  61 


B 

Babcock  Milk  Testers  ....  467,  468 

Babcock  Test  Bottles . 468 

Bag,  Ice . 204 

Bags,  Rubber  for  Gas . 445 

Balance  Cradle  Attachment,  T-Beam  26 

Balance  Cradles .  57 

Balance,  Inertia .  93 

Balance  Level .  44 

Balances  and  Weights . 45-63 

Balance  Support .  20 

Balance  Wheel,  Demonstration  .  .  66 

Balancing  Columns  Apparatus  .  .  130 

Balancing  Columns  Tube,  M.  G.  & 

B . 155 

Ball  and  Ring . 223 

Ballistic  Coil . 343 

Ball  Race . 301 

Balls,  all  kinds .  86 

Balsam  Bottles . 415 

Barker’s  Mill . 143 

Bar  Magnets . 278 

Barograph . 162 

Barograph  Charts . 162 

Barometer  Apparatus  . 148 

Barometer  Mounting  Board  ....  160 

Barometers . 160-162 

Barometer  Tubes . 148 

Barometer  Tubing . 491 

Baroscope  Balance . 144 

Baroscope  Bell  Glass . 145 

Baroscope  Bottle . 145 

Baroscopes . 144,  145 

Baro-Thermo  Recorder . 165 

Baro-Thermo  Recorder  Charts  .  .  .  165 

Bar,  Soft  Iron . 279 

Bases . 11,  12 

Basic  Clamps,  T-Beam  ....  25,  26 

Baths,  all  kinds .  409-411 


Batteries .  320-325 

Batteries,  Leyden  Jar . 303 

Batteries,  Thermo-Electric  ....  220 

Batteries,  Water .  297,  324 

Battery  Call  Telephone . 401 

Battery  Connectors  .  .  .  312,  313,  326 

Battery  Elements .  320-325 

Battery  Jars  .  . .  326,  451 

Battery  Rheostat  and  Switch  .  .  .  316 

Battery  Stands .  320,  321 

Beads,  Glass .  229,  411,  446 

Beaker  Brush .  419 

Beakers,  all  kinds  ....  204,  412,  413 


Beckmann's  Differential  Thermome¬ 


ters  . 216 

Bed  Clamp  for  Motor  Generator,  T. 

&  H . 390 

Beehive  Shelves . 445 

Beetz  Electroscope . 302 

Bell  and  Adjustable  Resonator  .  .  197 

Bell  Chimes .  300,  301 

Bell,  Electric,  Mounted . 158 

Bell  Glasses,  all  kinds . 154 

Bell  Glass  with  Sliding  Rod  ....  158 

Bell  in  Stirrup . 158 

Bell  in  Vacuo  Apparatus  .  .  .  144,  158 

Bellows .  202,  414 

Bells,  Electric . 319 

Belting,  Leather,  Round .  21 

Bench  Vise  Clamp .  90 

Bending  Beam  Apparatus .  94 

Bennett's  Electroscope . 294 

Bent  Arm  Lever  and  Supporting 

Table . 127 

Bent  Wire,  Mounted . 248 

Bent  Wire  with  Insulating  Handle 

and  Binding  Post . 284 

Bent  Wire  with  Weighted  Support 

and  Binding  Post . 284 

Beveled  Glass  Tube,  T.  &  H.  209 

Bezold’s  Tuning  Fork . 180 

Bibbs,  Demonstration . 144 

Bichromate  Potassium  Tablets .  .  .  468 

Bi-filar  Pendulum . 105 

Binding  Posts . 314,  315 

Binocular  Microscopes . 457 

Biology  Direction  Sheets . 496 

Biology  Furniture . 444 

Biology  (General)  Collection  Micro¬ 
scopic  Slides . 463 

Biot's  Hemispheres  ........  299 

Bi-polar  High  Frequency  Coil  .  .  .  380 

Bi-Prism,  Fresnel’s . 272 

Biram's  Anemometer . 168 

Birds'  Eggs . 413 

Bird  Skins,  unmounted . 413 

Birds,  mounted . 413 

Bit  Brace . 405 

Bits,  Augur . 405 

B-K  Solar  Calculator . 173,  174 

Black  and  White  Opaque  Screen  with 

Square  Opening,  F.  &  B.  ...  248 

Blackboard  Divider  or  Compass  .  .  71 

Blackboard  Drawing  Instruments.  .  71 

Blackened  Plate  of  Glass . 249 

Black  Opaque  Screen .  245,  248 

Blackprint  Paper . 280 

Blades,  Hack  Saw . 405 

Blast  Apparatus . 413 

Blast  Lamps  . .  201,  202 

Blast  Lamps,  Gasoline . 414 

Block,  Aluminum . 129 

Block  and  Bent  Wire . 248 

Block  Microscopes . 457 

Block  Plane . 405 

Blocks,  Charcoal . 422 

Blocks,  Waterproofed . 128 

Block  with  White  Face . 249 

Block,  Wood . 109 

Blower  Nets . 414 

Blowers . 414 

Blowpipe  Forceps.  Platinum  Tipped  473 

Blowpipe  Mouthpieces . 414 

Blowpipes . 414,  415 

Blowpipes,  Brazing . 414 

Blowpipes,  Dissecting . 433 


CATALOGUE  OF  SCIENTIFIC  INSTRUMENTS 


499 


PAGE 


Blowpipes,  Glass  Blowers’ . 415 

Blueprint  Paper . 280 

Board,  Connection,  F.  &  B.  ...  316 

Board,  Resistance . 355 

Board  Support  for  Composition  of 

Forces .  97 

Boats,  Combustion  . 425 

Bohnenberger’s  Gyroscope  ....  85 

Boilers,  Steam . 238 

Boiling  Point  of  Alcohol  Tube,  M.  & 

G . 209 

Bologna  Phials .  73 

Boltwood  Mercury  Pump . 151 

Bomb,  Freezing . 225 

Bone  Cutting  Forceps . 433 

Bone  Saw . 433 

Borers,  Cork . 426 

Botanical  Mounts . 480 

Botany  Microscope  Slides  .  .  .  462  ,  463 

Bottle  Brush . 419 

Bottle  Clamp .  19 

Bottle  Racks . 444 

Bottles,  all  kinds . 415-418 

Bottles,  Milk  and  Cream  Test  .  .  468 

Bottles,  Specific  Gravity . 130 

Bourdon  Gauge,  Demonstration  .  .  146 

Bovie’s  Auxanometer . 408 

Bow,  Double  Bass . 199 

Boxes,  Resistance .  357-362 

Boxes,  Slide . 461 

Box  with  Wire  Screen,  T.  &  H.  .  .  245 

Boyle's  Law  Apparatus  ....  147,  148 

Brace . 405 

Brain  Models . 469 

Brass  Wire . 311 

Brazing  Blowpipes . 414 

Breaking  by  Expansion  and  Contrac¬ 
tion  Apparatus . 224 

Breaking  Magnet . 278 

Breaking  Strength  of  Wires  Apparatus  96 

Breast  Drill . 405 

Breeding  Cages . 418 

Bridge  Model,  Davis'  . 124 

Bridge  Sight  Clinometer  Compass  .  287 

Bridge  Truss . 124 

Bristle  Stylus  and  Fixative  ....  191 

Brush,  Camel's  Hair .  60 

Brushes . 419 

Buchner  Funnel . 439 

Bulb,  Connecting,  Hopkins'  ....  419 

Bulb  Expander .  419 

Bulb,  Osmosis . 145 

Bulbs,  Gas  Ammonia . 445 

Bulbs,  Potash . 419 

Bull’s  Eye  Condensers . 460 

Bunsen  Blast  Lamps . 202 

Bunsen  Burners .  200,  201,  420 

Bunsen  Cell  .  . . 323 

Bunsen  Photometers .  243,  244 

Bunsen  Screen . 248 

Bunsen's  Ice  Calorimeter . 227 

Buoyancy  of  Liquids  Apparatus  .  .  135 

Burette  Attachment . 419 

Burette,  Automatic  Zero . 419 

Burette  Brush . 419 

Burette  Caps . 419 

Burette  Clamps . 423 

Burette  Float . 419 

Burette  Funnels . 419,  439 

Burettes . 419 

Burettes,  Acid . 468 

Burette  Supports . 484 

Burner  Attachments . 420 

Burner,  Illuminating .  240,  244 

Burner,  Monochromatic  Flame  .  .  .  240 

Burners,  all  kinds .  200-202  ,  420 

Burners,  Cluster . 420 

Burners,  Gang . 420 

Burners,  Glass  Blowers’ . 415 

Bursting  Squares . 157 

Buzzer . 319 


C 


Cabinet,  First  Aid . 405 

Cabinet  Makers'  Clamps . 423 

Cabinets .  6,  7 

Cabinet,  Tool . 405 

Cady  Insulated  Pinch  Connector  .  .  313 

Cages,  Breeding  for  Insects  ....  418 

Calcium  Chloride  Holder  for  Balances  42 1 

Calcium  Chloride  Jar . 451 

Calcium  Chloride  Tubes . 490 

Caliper  Arms  with  Vernier  ....  37 

Caliper  Gauges . '.  35 

Caliper  Rule .  37 

Calipers . 35-37 

Calorimeters  .* .  226-229 

Calorimetric  Thermometer  ....  216 


PAGE 

Camera  Lucid® . 460 

Camera  Obscura . 242 

Candelabrum  Trough . 244 

Candle  Experiment . 302 

Candle  Holders .  244,  248 

Candles . 239 

Candle,  Standard . 246 

Capacity  Test  Key . 318 

Capillary  Plates .  74 

Capillary  Tubes . 74,  75 

Capillary  Tubing . 491 

Caps,  Burette . 419 

Capstan  Arm  with  Capstan  ....  115 

Capsules . 421 

Carbon  and  Zinc  Battery  Connectors  326 

Carbon  Bisulphide  Prisms . 262 

CO2  Apparatus . 406 

Carbon  Dioxide  Freezing  Attachment  466 

Carbon  Electrodes . 403 

Carbon  Filters . 491 

Carbon  Paper . 101 

Carbon  Pencils . 159 

Carboy  Pump . 474 

Cardboard  Index  Strip,  F.  &  B.  .  .  266 

Carey-Foster  Bridge . 369 

Carpenter's  Level .  44 

Carre's  Freezing  Apparatus  ...  211 

Cars,  Inclined  Plane . 118,  121 

Cartesian  Diver . 137 

Cartilage  Knife . 433 

Cartridges,  Extraction . 436 

Case  of  Drawers . 444 

Casseroles . 421 

Catch  Bucket . 128 

Cathode,  Platinum . 473 

Cathode  Ray  Tubes .  308,  309 

Cat  Skins . 289 

Cell,  Floating . 328 

Cells,  Primary  and  Storage  .  .  320-325 

Cells,  Selenium . 401 

Celluloid  Friction  Strip . 289 

Celluloid  Rule .  33 

Cement,  Alundum . 406 

Center  of  Gravity  Apparatus  ...  100 

Center  of  Gravity  Arc . 100 

Center  of  Gravity  Board . 100 

Center  of  Gravity  System  ....  100 

Centrifugal  Dryer .  80 

Centrifugal  Force  Apparatus  .  .  77-85 

Centrifugal  Globe .  80 

Centrifugal  Hoop .  79 

Centrifugal  Railway . 106 

Centrifugal  Separator .  80 

Centrifugal  Tube.  Hall .  80 

Centrifuge  Accessories . 422 

Centrifuge  for  Rotator .  80 

Centrifuges . 422 

Chain,  Egg  and  Disc .  79 

Chains,  Conductor . 301 

Chamois  Skin . 403 

Chapman’s  Aspirators .  153,  407 

Charcoal  Blocks . 422 

Charge  and  Discharge  Key  ....  318 

Charging  Box,  Constant  Voltage  296 

Charging  Rods . 289 

Charles  Law  Tubes . 225 

Chart,  Atomic  Weight . 422 

Chart,  Graph .  71 

Chart,  Locomotive . 235 

Chart,  Metric  .  29 

Chart,  Periodic  Law  . 422 

Charts,  Barograph . 162 

Charts,  Baro-Thermo  Recorder  165 

Charts,  Electro- Dynamic . 398 

Charts,  Spectrum . 267 

Chart,  Star . 172 

Charts,  Thermograph . 165 

Chart.  Twilight .  172 

Cheese  Cloth  Bag . 280 

Chemical  Harmonica . 183 

Chemical  Labels . 452 

Chemical  Thermometers  .  .  .  214-216 

Chemistry  Direction  Sheets  ....  496 

Chemistry  Tables .  8 

Chimes,  Bell . 300 

Chimney,  Asbestos . 240 

Chimney,  Burner . 420 

Chimneys,  Lamp . 207 

Chisel . 405 

Chladni's  Figures  Apparatus  ....  194 

Chladni’s  Plate  Attachment.  T-Beam  26 

Chladni’s  Plate  Clamps . 194 

Chladni's  Plate  Sand . 194 

Chlorine  Tube . 490 

Circle  Area  Demonstration  Apparatus  68 

Circular  Protectors .  43 

Clamp  Holders . 423 

Clamp,  Pendulum,  T.  &  H .  104 

Clamps,  all  kinds .  13-26,  423 


PAGE 


Clamps,  Chladni’s  Plate . 194 

Clamps,  Stone's  Tension .  97 

Clasp  and  Hook  Rod,  Culler's.  .  .  105 

Clay  Pipes . 471 

Clinometer  Compass . 287 

Clinostats . 424 

Clips  for  Holding  Mirrors  to  Blocks  249 

Clock  Balance  Wheel .  66 

Clock  Contact .  64 

Clocks .  64,  66 

Coated  Paper  for  Vibrograph  .  .  .  191 

Cobalt  Bottle . 415 

Coddington  Magnifier . 452 

Coefficient  of  Friction . 109 

Cohesion  Discs .  73 

Coil,  Ballistic . 343 

Coil,  Induction,  M.  G.  &  B.  .  .  .  370 

Coil,  Magnetic  Induction . 329 

Coils,  Electromagnetic,  F.  &  B.  .  .  330 

Coils,  Electromagnetic,  M.  G.  &  B.  330 

Coils,  Gilley  Induction . 330 

Coils,  High  Frequency  ....  378-380 

Coils,  Induction .  373-375 

Coils,  Primary  and  Secondary  .  .  .  372 

Coils,  Repulsion . 329 

Coils,  Resistance .  354-356 

Coils,  Self  Induction . 387 

Coils,  Temperature . 354 

Collars .  16 

Collecting  Case . 492 

Collections,  Minerals  and  Rocks  .  .  469 

Collectors,  Gas . 445 

Collision  Ball  Apparatus .  89 

—  Color  Apparatus . 268 

Color  Discs .  81 

Colored  Glass  Plates . 267 

Combination  Rule  and  Level  ...  44 

Combustion  Boats . 425 

Combustion  Boat  Shields . 425 

Combustion  Boats,  Platinum  .  .  .  473 

Combustion  Furnace . 440 

Combustion  Tubing .  489,  492 

Commutators . 319 

Comparative  Thermometer  ....  213 

Comparing  Scale .  34 

Compasses .  70,  71 

Compasses,  Magnetic .  286,  287 

Compensating  Pendulums .  65 

Compensation  Apparatus . 221 

Composition  of  Force  and  Motion 

Apparatus .  99 

Composition  of  Force  Boards  .  .  97—99 

Composition  of  Forces . 96-99 

Compound  Achromatic  Prisms  .  261,  271 

Compound  Bars  . 223 

Compound  Lever  and  Jackscrew  .  .  126 

Compound  Levers . 109,  126 

Compound  Magnets . 278 

Compound  Microscopes  ....  454-457 

Compound  Rod . 207 

Compressed  Air  Outfits . 152 

Compression  Bibbs,  Demonstration  .  144 

Compression  Pump  for  Boyle’s  Law  147 

Compression  Pumps . 151,  152 

Concave  and  Convex  Cylindrical 

Mirror . 249 

Concave  and  Convex  Mirrors  .  .  .  249 

Concave  and  Convex  Spherical  Mirror  249 
Concave  Galvanometer  Mirrors  .  .  348 

Concave  Glass  Mirror,  Mounted  .  .  244 

Concave  Lenses .  258,  259 

Concentric  Rings . ,.  .  .  476 

Condenser  Attachment,  Culler's  .  .  227 

Condenser  Clamps . 423 


Condenser  Plate  Attachment,  Elec¬ 


troscope . 294 

Condenser  Plates . 304 

Condensers . 425 

Condensers,  Air . 388 

Condensers,  Bull's  Eye . 460 

Condensers,  Liebig's . 211,  425 

Condenser,  Soxhlet's . 425 

Condensers,  Paper,  Mica . 388 

Condensers,  Plate . 304 

Condensers,  Substage  Abbe  ....  459 

Condensers,  Wireless .  383 

Condenser,  Wireless  Fixed . 384 

Condensing  Lenses  .  .  •  ■  258,  259 

Conduction  Tube,  Liquid . 208 

Conductivity  of  Water  Apparatus  .  208 

Conductivity  Rods . •  •  207 

Conductometers .  207,  208 

Conductor  Chains.  . 301 

Conductors,  Electrostatic  .  .  .  298-300 

Cone  and  Plane . 106 

Cone,  Dissectible . 

Cone,  Sphere  and  Cylinder  ....  68 

Conical  Graduates . 44' 

Conical  Net,  Faraday’s  Net  ....  300 


5oo 


L.  E.  KNOTT  APPARATUS  CO 


> 


BOSTON 


PAGE 


PAGE 


PAGE 


Conjugate  Foci  Screen . 245 

Connecting  Tips . 312,  313 

Connecting  Tubes . 490 

Connection  Board,  F.  &  B . 316 

Connector,  High  Potential  ....  313 

Connectors,  Binding  Post  .  .  .  314,  315 

Constant  Voltage  Charging  Box  .  .  296 

Constant  Volume  Air  Thermometers  218 
Constant  Volume  Hydrometer  Tube, 

M.  G.  &  B . 131 

Constant  Weight  Hydrometer  Tube, 

M.  G.  &  B . 131 

Contact  Keys  . . 317 

Controller  Model . 397 

Convectional  Current  Apparatus  .  .  207 

Convex  and  Concave  Mirrors  .  .  .  249 

Convex  Glass  Mirror,  mounted.  .  .  244 

Convex  Lens  and  Wire  Screen, 

mounted,  M.  G.  &  B . 248 

Convex  Lenses .  258  ,  259 

Cooling  Cup,  T.  &  H . 206 

Coplin’s  Staining  Jar . 451 

Copper  Anode . 403 

Copper  Beakers . 413 

Copper  Electrodes . 403 

Copper  Plating  Outfit . 403 

Copper  Shot . 229 

Copper  Sulphate . 403 

Copper  Wire . 311 

Cord,  Pulley  .  .  .  .  • . Ill 

Cores,  Wooden  with  Attached  Bind¬ 
ing  Posts,  F.  &  B . 313 

Cork  Borers . 426 

Cork  Borer  Sharpeners . 426 

Cork  Knife . 426 

Cork  Mats . 426 

Cork  Presses . 426 

Corks . 426 

Cork  Screw . 426 

Cork  Sheet . 426 

Corrosive  Sublimate  Tablets  ....  468 

Counterpoise  for  Trip  Scale  ....  55 

Counterpoise  Gyroscope .  85 

Coupling,  Brass . 156 

Couplings,  Hydrant .  153  ,  407 

Cover  Glasses . 461 

Cover  Glass  Forceps . 433 

Cowen's  Expansion  Apparatus  .  .  .  221 

Crane  Boom,  F.  &  B . 120 

Crane  Demonstration  Apparatus  .  .  120 

Crane,  Hoisting . 123 

Creamometer  Jar . 468 

Cream  Test  Bottles . 468 

Crooke's  Radiometers  . 204 

Crooke’s  Tubes .  308,  309 

Cross  Bars,  Metal .  10 

Cross  Cut  Saw . 405 

Cross  Section  Paper .  70,  101 

Crova’s  Disc .  82 

Crowfoot  Gravity  Cell . 322 

Crown,  Burner . 420 

Crown  Glass  Prisms .  261,  271 

Crucible  Blocks . 429 

Crucible  Funnels .  428,  429 

Crucible  Furnaces .  440,  442 

Crucible  Rubber  Tubing . 429 

Crucibles,  all  kinds .  427-429 

Crucibles,  Platinum . 473 

Crucible  Tongs . 429 

Cryophorouses . 211,  212 

Crystallizing  Dishes . 430 

Crystal  Models .  68 

Cube,  Paraffine .  129 

Cube  Root  Block .  68 

Cubes,  Glass  .  . . 256 

Cubes,  Wood .  31 

Cubical  Expansion  Bulb . 212 

Cubical  Mirror .  82 

Cubic  Foot  Block .  30 

Culler’s  Index  of  Refraction  of  Water 

Apparatus . 256 

Culler's  Lever,  Pulley,  Pendulum, 

Clasp  and  Hook  Rod .  105 

Culler’s  Principle  Focus  Box  .  .  .  248 

Culture  Tubes . 490 

Cups,  Porous . 429 

Curtis  Naturalistic  Models  .  .  175-178 

“  Cut-off”  Clamps . 423 

Cutters,  Glass . 447 

Cylinder,  Aluminum . 129 

Cylinder  and  Bucket . 128 

Cylinder,  Hollow  Brass,  M.  G.  & 

B .  68 

Cylinder,  Loaded,  Waterproofed  .  128 

Cylinders,  Graduated  .  .  .  429,  447,  451 
Cylinders,  Hydrometer  ....  429.  451 

Cylinder  Wheel,  Loaded .  100 

Cylindrical  Diaphragm . 239 

Cylindrical  Glass  Vessel . 135 


Cylindrical  Iron  Armature,  T.  &  H1.  279 


Cylindrometer .  37 

D 

Dairy  Thermometer . 468 

Dancing  Balls  and  Holder  ....  301 

Daniell  Cell . 322 

Darning  Needles . 279 

D'Arsonval  Galvanometer,  M.  G.  & 

B . 342 

D'Arsonval  Galvanometers  .  .  337-346 

Davis’  Model  Bridge . 124 

Davy’s  Safety  Lamp . 208 

Deflagrating  Spoons . 479 

Deflection  Magnetometer . 282 

De  La  Rives  Apparatus . 308 

Demonstration  Aneroid  Barometer  .  161 

Demonstration  Arc  Lamps  .  .  159  .  404 
Demonstration  Batteries  .  .  .  320,  321 
Demonstration  Dip  Needle  ....  285 

,  Demonstration  Electromagnets  .  .  331 

Demonstration  Hydraulic  Ram  .  ,  139 

Demonstration  Hydrometer  ....  131 

Demonstration  Incandescent  Lamp  159 
Demonstration  Inclined  Plane  ...  118 

Demonstration  Induction  Coils  .  .  373 

Demonstration  Lenses  ....  258,  259 

Demonstration  Lever  . . 109 

Demonstration  Leyden  Jar  ....  303 

Demonstration  Metallic  Thermometer  213 
Demonstration  Microscope,  M.  &  G.  266 
Demonstration  Motor-Dynamo  .  .  391 

Demonstration  Organ  Pipes  ....  184 

Demonstration  Telephone  Receiver  .  400 

Demonstration  Transformer  ....  370 

Demonstration  Wheatstone  Bridges 

366.  367 

Density  Apparatus . 128-131 

Density  by  Flotation . 129 

Density  Cubes .  31 

Density  Indicating  Ball  . 130 

Derrick . 124,  125 

Dessicator  Dish . 430 

Dessicator  Plates . 430 

Dessicators . 430 

Detents  for  Meter  Stick .  88 

Dewar  Beaker,  Unexhausted  ....  208 

Dewar  Bulb . 208 

Dewing’s  Air  Tester . 406 

Dew  Point  Apparatus . 212 

Diagonal  Scales .  34,  40-42 

Diamagnetic  and  Paramagnetic  Study 

Apparatus . 333 

Diamagnetic  and  Paramagnetic  Sub¬ 
stances  . 279 

Diamond  for  Writing  on  Glass.  .  .  430 

Diamond  Ink . 450 

Diaphragms . 239 

Diaphragm  with  One  Cm.  Opening, 

T.  &  H . 248 

Dibdin  Bunsen  Photometer  .  .  243,  244 

Differential  Pulley  Hoists . 113 

Differential  Thermoscopes . 217 

Diffraction  Gratings . 273 

Diffusion  Shells .  75,  145 

Digesting  Shelves . 430 

Digestion  Flasks . 438 

Digestors,  Papin  .  .  .  . . 209 

Dip  Needles . 286 

Direction  Sheets,  Biology . 496 

Direction  Sheets,  Chemistry  ....  496 

Direction  Sheets,  Physics .  27 

Direct  Vision  Pocket  Spectroscope  269 

Direct  Vision  Prisms .  261,  263 

Disc,  Brass,  M.  G.  &  B .  68 

Dischargers . ’.  .  .  298,  301 

Disc,  Magnetized . 278 

Disc,  Revolving . 302 

Discs,  Cohesion  and  Adhesion  ...  73 

Discs,  Rubber,  for  Blowers  .  .  414.  477 

Dishes,  all  kinds .  430-432 

Dishes,  Platinum . 473 

Dissected  Clock .  64 

Dissectible  Cone .  68 

Dissectible  Hand  Power  Dynamo 

and  Motor . 394 

Dissectible  Induction  Coil . 373 

Dissectible  Transformer . 371 

Dissecting  Instruments  ....  433,  434 
Dissecting  Microscopes  ....  457,  458 

Dissecting  Pan . 433 

Dissecting  Sets . 434 

Distillation  FlasksJ  . 438 

Distillation  Tubes,  Fractional  .  .  .  435 

Distilling  Apparatus .  435,  482 

Diverging  Ray  Attachment  ....  254 

Dividers .  70 

Diving  Bell  Model . 157 


Dixon’s  Crucibles . 427 

Double  Bass  Bow . 199 

Double  Connectors . 315 

Double  Contact  Keys . 317 

Double  Dishes . 432 

Double  Meter  Stick .  32 

Doublet  Magnifiers . 453 

Double  Wall  Calorimeters  .  .  .  227,  228 

Double  Wall  Funnels . 439 

Douglass’  Double  Contact  Key  .  .  317 

Drawing  Boards .  70 

Drawing  Instruments  . 69-71 

Drawing  Sets . ' .  69 

Drill,  Breast . 405 

Drive  Pulley  for  Round  Belt  ...  78 

Drive  Wheel  and  Clamp .  21 

Dropping  Bottles . 415 

Dry  Cell . 325 

Drying  Ovens . 435 

Drying  Paper . 472 

Drying  Table,  Section . 466 

Drying  Tower . 451 

Drying  Tubes . 490 

Dry  Measures .  32 

Duff's  Acceleration  Apparatus  .  .  .  101 

Dynamo  and  Motor,  Hand  Power  .  394 
Dynamometers  .........  56-57 

Dynamo-Motor . 390 

Dynamos  and  Motors  ....  389-397 

Dynamos,  Small .  389,  390 


E 


Ear  Model . 469 

Earth  Induction  Apparatus  ....  83 

Earth  Inductor . 288 

Ear  Trumpet  . . 187 

Eccentric  Leveling  Bases .  12 

Eggs,  Birds’ . 413 

Eight-in-One  Apparatus  . . 136 

Einhorn's  Saccharometer . 478 

Elasticity  of  Wire  Apparatus  ...  95 

Electric  and  Steam  Power  Plant .  .  238 

Electric  Appliances . 436 

Electric  Bell,  Mounted . 158 

Electric  Bells . 319 

Electric  Calorimeters . 228 

Electric  Centrifuges  . . 422 

Electric  Compressed  Air  Outfit  .  .  152 

Electrical  Density  Apparatus  .  .  .  299 

Electric  Driven  Tuning  Fork  .  .  .  181 

Electric  Furnace  Cores . 443 

Electric  Furnaces  ....  404,  440—443 

Electric  Gong . 319 

Electric  Incubators . 450 

Electric  Iron . 436 

Electric  Lamp . 240 

Electric  Mortar . 302 

Electric  Rotator .  78 

Electric  Screen . 299 

Electric  Soldering  Iron . 436 

Electric  Stoves .  436,  483,  484 

Electric  Water  Baths . 411 

Electric  Water  Heater .  436 

Electrodes,  Carbon,  Copper,  Plati¬ 
num  . 403 

Electrodynamic  Apparatus  .  .  .  376,  398 

Electrodynamic  Charts . 398 

Electrolysis  Apparatus  ....  402  ,  403 
Electrolysis  Apparatus,  Lantern  .  .  403 

Electrolysis  Tube  Supports  ....  403 

Electrolytic  Interrupters . 375 

Electrolytic  Rectifiers . 385 

Electromagnetic  Coils,  F.  &  B.  .  .  330 

Electromagnetic  Coils,  M.  G.  &  B.  330 

Electromagnets .  330-333 

Electromagnets,  mounted  .  .  .  332,  333 
Electrometer  Charging  Box  ....  296 

Electrometer,  Quadrant . 302 

Electrometers .  293-296 

Electrophorouses . 290 

Electroplating  Materials . 403 

Electroplating  Outfit . 403 

Electroscope,  Beetz . 302 

Electroscopes .  293-296 

Electrostatic  Motor . 302 

Electrostatic  Sets .  201 ,  302 

Electrostatic  Wrhirl . 301 

Electrotyping  Letters,  T.  &  H.  .  .  403 

Elements,  Battery .  320-325 

Ellipsoidal  Conductor . 299 

Emery,  Powdered . 403 

Endless  Screw . 120 

Endosmometer . 75.  145 

End  Supports .  13 

Engines,  Gas . 232 

Engines,  Hot  Air . 231 

Engines,  Steam .  233-238 


CATALOGUE  OF  SCIENTIFIC  INSTRUMENTS 


50i 


PAGE 

Geometric  Stands .  15 

Geometrical  Wooden  Forms  ....  67 

German  Silver  Wire . 311 

Gilder’s  Knife,  Pad  and  Tip  .  .  293 

Gilley  Coils . 330 

Gilley  Gramme  Machine . 392 

Gilley  Low  Form  Bunsen  Burner  .  200 

Gilley  Skidmore  Battery . 320 

Gimlet . 405 

Glass  Beads .  229,  411,  446 

Glass  Beakers . 412 

Glass  Blowers’  Blowpipes . 415 

Glass  Cutters . 447 

Glass  Cutting  File . 437 

Glasses,  Bell,  all  kinds . 154 

Glasses,  Test .  446,  487 

Glass  Friction  Rods . 289 

Glass,  Hand  and  Bladder . 154 

Glass  Models  of  Crystals .  68 

Glass  Mortars . 470 

Glass  Penetrating  Apparatus.  .  .  .  302 

Glass  Plate  Lacquered  Black  on  Back  249 

Glass  Plates . 472 

Glass  Retorts . 476 

Glass  Rods . 477 

Glass  Slides,  Microscopic . 461 

Glass  Stopcocks  . . 483 

Glass  Tube  and  Steel  Filings  .  .  .  278 

Glass  Tube  Cutters . 447 

Glass  Tubing . 491 

Glass  Wool . 447 

Glazed  Paper . 471 

Gold  Beaters'  Skin . .  .  447 

Gold  Leaf . 293 

Gold  Leaf  Cutting  Apparatus  .  .  293 

Gong,  Electric . 319 

Gooch  Crucibles . 428 

Gooch  Crucibles,  Platinum.  .  .  .  473 

Gotham  Cell . 321 

Gotham  Demonstration  Battery  .  .  321 

Graduated  Arc  with  Clamp  .  .  89,  90 

Graduated  Cardboard  Screen  .  .  245 
Graduated  Cylinders  .  .  .  429,  447,  451 

Graduated  Flask . 406 

Graduated  Pipettes . 406 

Graduated  Rods,  Metal .  10 

Graduates,  all  kinds . 447 

Graph  Chart .  71 

Graphic  Analysis  of  Sound  Waves  .  196 

Gratings,  Diffraction  . 273 

Graphite  Crucibles . 427 

Graphite  Resistances . 365 

Gravesend  Ball  and  Ring . 223 

Gravity  and  Motion  Apparatus  .  .  106 

Gravity  Cell . 322 

Grenet  Batteries . 323 

Guard  Plugs,  Brass . 156 

Guinea  and  Feather  Tube . 102 

Gummed  Labels . 452 

Gyroscopes . 84,  85 

Gyroscopic  Outfit .  85 


PAGE 


Entomological  Mounts . 480 

Equilateral  Prism,  M.  &  G .  256 

Equilaterial  Prisms  ....  260-263,  271 

Equilibrium  Apparatus .  100 

Equipotential  Apparatus . 284 

Erdmann’s  Float . 419 

Erlenmeyer  Flasks . 438 

Ether  Freezing  Attachment  ....  466 

Eudiometers . 436 

Evaporating  Dishes . 431 

Exciting  Pads  .  . . 289 

Expander,  Bulb . 419 

Expansion  and  Contraction  appara¬ 
tus,  Packard’s . 224 

Experimental  Barometer  Vacuum  and 

Geissler  Tube  ..........  307 

Extension  Clamps .  14 

Extension  Rings . 476 

Extraction  Apparatus,  Soxhlet's  .  .  436 

Extraction  Cartridges . 436 

Extraction  Flasks . 438 

Extraction  Thimbles . 436 

Extraction  Tubes,  Soxhlet’s  ....  436 

Eyeglass  Protector . 310 

Eye  Models .  259,  469 

Eye  Shades . 245 


F 

Falling  Body  Apparatus  .  101-103 

Falling  Body  Apparatus,  M.  &  G.  102 

Faraday’s  Net . 300 

Faraday’s  Ring . 370 

Faraday’s  Shield . 299 

Farrington’s  Alkaline  Tablets  .  .  .  468 

Faucets,  Water .  9 

Fechner’s  Electrometer . 294 

Fermentation  Tubes . 491 

Ferron  Detector . 384 

Fessel's  Gyroscope  .  '. .  85 

Field  Tray . 284 

Filaments  for  Demonstration  Incan¬ 
descent  Lamp  .  .  .  . ' . 159 

Files .  405,  437 

Filings  Sifter .  . . 280 

Film  Demonstration  Apparatus.  .  .  73 

Filter  Cones,  Alundum . 437 

Filter  Cones,  Platinum . 473 

Filter  Crucibles . 428 

Filter  Dishes . 432 

Filtering  Flasks . 438 

Filter  Paper,  all  -  kinds . 437 

Filter  Plates .  437,  472 

Filter  Pumps .  153,  407 

Filter  Tubes . 491 

Fire  Engine  Pump . 140 

Fireless  Cooker . 208 

Fire  Syringe . 231 

First  Aid  Cabinet . 405 

Fitz  Air  Tester . 406 

Flannel  Cap  with  Attached  Silk 

Cords,  M.  &  G . 289 

Flannel  Exciting  Pad . 289 

Flask,  Graduated . 406 

Flasks,  all  kinds .  438,  439 

Flexible  Steel  Gas  Tubing  ....  477 

Flexible  Wire . 311 

Flexure  of  Beam  Apparatus  ....  94 

Flint  Glass  Prisms .  261,  271 

Float,  Burette . 419 

Floating  Helix  and  Cell . 328 

Floating  Magnets . 279 

Florence  Flasks . 438 

Fluorescent  Geissler  Tubes  .  .  305,  306 

Fluoroscopes . 310 

Flush  Plates .  12 

Foil,  Platinum . 473 

Foil.  Tin .  293,  487 

Folding  Rule .  34 

Foot  Blowers  or  Bellows  .  .  .  202,  414 

Forceps . 439 

Forceps.  Balance .  60 

Forceps,  Bone  Cutting . 433 

Forceps,  Cover  Glass . 433 

Forceps,  Dissecting . 433 

Forceps,  Platinum  Tipped . 473 

Force  Pumps . 140 

Forces  in  a  Uniform  Metal  Bar  with 

a  Sliding  Load .  126 

Fortin  Cistern  Barometers  ....  160 

Foucault’s  Pendulum .  79 

Foucault's  Prisms . 275 

Fountain  in  Vacuo . 153 

Four  Way  Gas  Turret,  Mounted  .  445 

Fractional  Distillation  Tubes.  .  .  .  435 

Fractional  Weights . 59,  61 

Franklin’s  Palm  or  Pulse  Glass  .  .  211 

Freas'  Osmosis  Apparatus  .  .  .  75,  145 


PAGE 

Free  Fall  Acceleration  Apparatus  102,  103 


Freezing  Apparatus  ....  159,  211,  212 

Freezing  Attachments . 466 

Freezing  Bomb . 225 

Frequency  Indicator . 398 

Fresenius’  Burettes  .  .  .  1 . 419 

Fresnel’s  Bi-Prism . 272 

Fresnel's  Mirrors . 272 

Friction  Apparatus . 109 

Friction  Block . 109 

Friction  Board . 109 

Friction  of  Air  Apparatus . 146 

Friction  of  Water  Apparatus,  Hall  73 
Friction  Rod  and  Magnet  Support  .  279 

Friction  Rods . 289 

Fruit  Jars . 451 

Fuller  Bibb,  Demonstration  ....  144 

Fuller  Cell . 322 

Funnel,  Acid . 468 

Funnel,  Burette . 419 

Funnel,  Mercury  Storage  ....  146 

Funnels,  all  kinds . 439 

Funnels  for  Hot  Filtrations  ...  439 

Funnel  Supports .  484,  485 

Funnel,  Wood  for  Porosity  ...  72 

Furnace  Cores . 443 

Furnace,  Electric . 404 

Furnaces  .  440-443 

Furniture.  Laboratory  ....  2-9,  444 

Fused  Silica  Beakers . 413 

Fused  Silica  Capsules . 421 

Fused  Silica  Casseroles . 421 

Fused  Silica  Combustion  Boats  .  .  425 

Fused  Silica  Crucibles . 428 

Fused  Silica  Dishes . 432 

Fused  Silica  Evaporating  Dishes  .  .  431 

Fused  Silica  Plates . 472 

Fused  Silica  Rods . 477 

Fused  Silica  Trays . 488 

Fused  Silica  Triangles . 488 

Fused  Silica  Tubing . 489 

Fused  Silica  Ware . 494 

Fuse  Wire . 311 


G 

Galileo’s  Telescope  Model . 266 

Galton’s  Whistles . 184 

Galvanometer  Accessories  .  .  .  348,  349 

Galvanometer  Mirrors . 348 

Galvanometers .  334-346 

Galvanometer  Suspension  Filaments  348 

Galvanometer  Telescope  and  Scale  349 

Galvanoscopes . 334 

Gas  Ammonia  Bulbs . 445 

Gas  Apparatus . 445 

Gas  Bags  .  .  .  . . 445 

Gas  Bottle  Generator . 445 

Gas  Cocks . 9.  445 

Gas  Collectors . 445 

Gas  Engine  Model . 232 

Gas  Engines . 232 

Gas  Generators . 445 

Gas  Holders . 446 

Gas  Lamp . 240 

Gas  Measuring  Tubes . 446 

Gasoline  Burner . 202 

Gasoline  Gas  Generator . 445 

Gasometers . 446 

Gas  Pressure  Apparatus . 146 

Gas  Pressure  Regulator . 446 

Gas  Regulators . 446 

Gas  Sample  Tubes . 445 

Gas  Stopcocks . 445 

Gas  Stoves . 483 

Gas  Tubes .  446.  491 

Gas  Tubing . 477 

Gas  Turrets . 445 

Gauge  Calipers .  35 

Gauges,  Pitch .  405 

Gauges,  Pressure . 155 

Gauges,  Pressure  and  Vacuum  ...  146 

Gauge,  Pressure,  for  Apparatus  A  .  203 

Gauge,  Thorpe . 229 

Gauges,  Wire .  39 

Gauze,  all  kinds . 446 

Gauze  Top,  Burner . 420 

Gay  Lussac’s  Support . 484 

Geared  Wheels .  120 

Geissler’s  Burettes . 419 

Geissler  Tube,  Experimental  ....  307 

Geissler  Tube  Holder .  301,  307 

Geissler  Tube  Rotators . 307 

Geissler  Tubes .  305-308 

Geissler  Tubes,  Unequally  Evacuated  307 

Generator,  Gas  Bottle . 445 

Generators . 397 

Genus  Covers  .  .  .  - . 472 


H 


Hackeling's  Tellurian . 170 

Hack  Saw . 405 

Hack  Saw  Blades . 405 

Haematokrit . 422 

Half  Meter  Stick .  32 

Half  Meter  Wheatstone  Bridges  .  .  368 

Hammers  . 405 

Hammers,  Rubber .  .  179 

Hand  Air  Pumps . 149,  151 

Hand  and  Bladder  Glass . 154 

Hand  Balances .  56 

Hand  Balance  Support .  20 

Hand  Bellows . 202 

Hand  Drive  Centrifuges . 422 

Hand  Microtome . 464 

Hand  Power  Dynamo  and  Motor  .  394 

Hand  Screw  Clamp . 423 

Harcourt  Ball-bearing  Pulleys  .  110,  111 
Hardened  Steel  Rods  ......  279 

Hare’s  Apparatus . 130 

Harmonic  Motion  Apparatus.  .  .  93 

Harness  for  Trip  Scale .  55 

Hatchet . 405 

H-Bases .  12 

Head  Models . 469 

Heart  Model . 469 

Heater,  Hot  Water . 201 

Heaters,  Soldering  Iron . 479 

Heating  Coil  Attachment  for  Calo¬ 
rimeters . 228 

Heat  Shield . 211 

Hefner  Lamps . 246 

Heliopticons . 239 

Heliostats . 239 


502 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  » 


PAGE 


PAGE 


PAGE 


Helix  and  Ring . 331 

Helix  and  Separable  Magnetic  Cir¬ 
cuit  . 331 

Helix  Electromagnet . 331 

Helix,  Wireless . 383 

Helix  with  Movable  Coil . 331 

Helmholtz  Resonators . 197 

Hero's  Fountain . 141 

High  Frequency  Apparatus  .  .  378-382 

High  Frequency  Coils  ....  378-380 

High  Frequency  Inductive  Apparatus  379 

High  Frequency  Phenomena  Appa¬ 
ratus  .  380,  381 

High  Resistance  Wire . 311 

High  Temperature  Thermometers.  .  216 

High  Tension  Keys . 317,  318 

High  Vacuum  Aspirator . 407 

Hoffman’s  Clamp . 423 

Hoffman’s  Electrolysis  Apparatus  402 

Hoisting  Crane .  123,  124,  125 

Holder,  Calcium  Chloride,  for  Bal¬ 
ances  . 421 

Holder,  Electrostatic . 301 

Holder,  Geissler  Tube . 307 

Holder,  Incandescent  Lamp  ....  244 

Holders,  Clamp . 423 

Hollow  Induction  Cylinder  ...  299 

Hollow  Lenses . 259 

Hollow  Prisms . 262 

Hollow  Troughs  ...  ....  272 

Holman’s  Life  Slide . 461 

Hook  Collars .  16 

Hooke’s  Law  Apparatus  ...  95 

Hooks  and  Chains,  Dissecting  .  .  433 

Hook,  Threaded . 120 

Hook,  U-shaped,  T.  &  H .  109 

Hoop,  Centrifugal .  79 

Hopkins’  Connecting  Bulb .  419 

Hopkins’  Forked  Tube .  188 

Horizontal  Galvanometer . 342 

Horn  Spatulas . 479 

Horn  Spoons . 479 

Horse  and  Rider . 100 

Horseshoe  Core,  Soft  Iron,  M.  G.  &  B.  279 

Horseshoe  Magnets . 278 

Hortvet's  Apparatus . 116 

Hot  Air  Engines . 231 

Hot  Plates .  409  ,  483  ,  484 

Hot  Water  Heater . 201 

Household  Thermometers  .  .  .  163,  213 

Humidity  Apparatus . 166,  167 

Huyghenian  Oculars . 459 

Hydrant  Couplings . .  153  ,  407 

Hydraulic  Presses .  138 

Hydraulic  Rams . 139 

Hydrodynamic  Wheatstone  Bridge  .  366 

Hydrogen  Absorption  Apparatus, 

Hall . 403 

Hydrometer  Jars .  131,  429  ,  451 

Hydrometers,  all  kinds  ....  131,  448 

Hydrometer  Tubes . 131 

“Hydrone"  Cartridges . 445 

Hydrostatic  Balances . 53,  54 

Hydrostatic  Bellows .  138 

Hydrometers . 166,  167 

Hygrophant . 167 

Hyperdermic  Syringe . 486 

Hypsometers . 203 

Hvpsometer  Thermometers . 216 


I 

Ice  Bag . 204 

Ice  Calorimeter .  227 

Iceland  Spar . 274 

Ice  Shredder  and  Shave . 204 

Ice  Tray . 204 

Ignition  Apparatus . 302 

Ignition  Capsules . 421 

Ignition  Tubes . 491 

Illuminating  Burners .  240,  244 

Image  on  Rod . 245 

Image  Plates . 300 

Images,  Pith . 300 

Impactand  Reflection  Attachment  .  88 

Impact  Apparatus . 87,  90 

Impenetrability  Apparatus .  76 

Incandescent  Lamp,  Demonstration  159 
Incandescent  Lamp  Holder  ....  244 

Incidence  and  Reflection  Apparatus  250 

Incinerating  Dishes . 432 

Inclined  Plane  and  Cone . 106 

Inclined  Plane  Cars .  118 

Inclined  Plane  Rollers . 117,  121 

Inclined  Planes . 117,  118 

Inclined  Wire  Acceleration  Apparatus  103 
Incompressibility  of  Liquids  Appa¬ 
ratus  . .  .  76 


Incubators .  449  ,  450 

Indelible  Pencil . 471 

Index  Block . 249 

Index  of  Refraction  Apparatus  256,  257 
Index  of  Refraction  Plates  ....  256 

Index  Strip,  Mounted,  Hall’s  ...  94 

Indicating  Meters .  474,  475 

Indicator,  Frequency . 398 

Inductances . 387 

Induction  and  Distribution  Spheres 

298  299 

Induction  Coil,  M.  G.  &  B.  ...  370 

Induction  Coils .  284,  373-375 

Induction  Coils,  Gilley . 330 

Induction  Cylinders .  298,  299 

Induction  Motors . 396 

Induction  Study  Apparatus  ....  330 

Inductive  Apparatus,  High  Fre¬ 
quency  . 379 

Inertia  Accessories,  Magnetometer  .  281 

Inertia  Apparatus .  76 

Inertia  Balance .  93 

“Influence  Machines .  290-292 

Ink,  Diamond . 450 

Inoculating  Needle . 470 

Insect  Cages . 418 

Insect  Pins . 471 

Insect  Specimens . 480 

Inside  Calipers .  35 

Instantaneous  Hot  Water  Heater  201,  493 

Instructor's  Tables . 5,  405 

Instruments,  Dissecting  ....  433,  434 

Instrument  Shelters . 169 

Instruments,  Telegraph . 400 

Insulating  Stands . 297 

Insulating  Stools . 297 

Interference  Apparatus  ....  187,  188 

Interference  Mirrors . 272 

Interference  of  Light  Plates,  M.  & 

G . 273 

Interference  Tubes . 188 

Interhooking  Laboratory  Weights  .  62 

Intermittent  Fountain . 137 

Interrupter,  Make  and  Break  .  .  .  372 

Interrupters,  Electrolytic . 375 

Interrupting  Wheel . 318 

Interval  Timer .  64 

Inverse  Squares  Model . 242 

Inverted  Show  Jars . 451 

Iron  Armatures,  T.  &  H . 279 

Iron  Clad  Magnets . 331 

Iron  Crucibles . 427 

Iron,  Electric . 436 

Iron  Filings . 280 

Iron  Mortars . 470 

Iron  Retorts . 476 

Iron  Weights .  62,  63,  127 

Iron  Wire . 311 


J 

Jackscrew  and  Compound  Lever  .  .  126 

Jack  Screws . 119 

Jar,  Creamometer . 468 

Jars,  all  kinds . 451 

Jars,  Aquaria . 406 

Jars,  Glass . 131 

Jars,  Hydrometer  .  .  :  131,  429  ,  451 

Jars,  Rectangular,  Battery  ....  326 

Jars,  Round,  Battery . 326 

Jenkins’  Specific  Gravity  Apparatus  72 

Joints,  Models . 470 

Jolly  Balances .  56 

Jolly  Photometer,  F.  &  B . 243 

Junker’s  Calorimeter . 229 


K 

Kaleidoscopes . 251 

Kempe's  Charge  and  Discharge  Key  318 

Kerosene  Lamps . 240 

Key  and  Sounder,  Combined  .  .  .  400 

Key  Hole  Saw . 405 

Key  Parts,  Telegraph . 400 

Keys,  High  Tension . 317,  318 

Key,  Telegraph . 400 

Kittredge  Clamps .  109 

Kjeldahl  Flasks . 438 

Kjeldahl’s  Digesting  Shelves  ....  430 

Knife  Back,  Microtome . 466 

Knife,  Cork . 426 

Knife  Edge  Attachment,  T-Beam  .  26 

Knife  Edge  Bracket .  16 

Knife  Edge  Clamps . 16,  26 

Knife  Edge  Contact  Piece  ....  94 

Knife  Handle.  Microtome . 466 

Knife  Strop,  Microtome . 466 


Knife  Switch  Pole  Changer  ....  319 

Knitting  Needles . 279 

Knives,  Microtome . 466 

Koch's  Funnel . 439 

Kolbe  Harcourt  Optical  Disc  .  252,  254 

Kuehne’s  Eye  Model . 259 

Kullmer  Star  Chart . 172 

Kundt’s  Apparatus . 199 

Kundt’s  Interference  Apparatus  .  .  187 

Kymograph  Record  Sheets . 192 

Kymographs . 192 


L 


Labels,  Chemical . 452 

Labels,  Gummed . 452 

Labels,  Microscopic  Slide . 452 

Laboratory  Clock .  64 

Laboratory  Furniture . 2-9 

Laboratory  Microtomes  ....  464,  465 

Laboratory  Stand .  14 

Laboratory  Steelyard . 126 

Lactometers .  448,  468 

Ladle . 452 

Lambert’s  Capacity  Test  Key  .  .  .  318 

Laminated  Magnet  High  School  Gal¬ 
vanometer  . 342 

Laminated  Magnet  Lecture  Table 

Galvanometer . 341 

Lamp  and  Scale . 348 

Lamp  Board . 363 

Lamp  Chimneys . 207 

Lamp  Cord . 311 

Lamp,  Demonstration  Arc  .  .  159  .  404 

Lamp,  Demonstration  Incandescent  159 

Lamp,  Electric . 240 

Lamp,  Gas . 240 

Lamp,  Microscope . 460 

Lamps,  Alcohol .  201,  202,  452 

Lamps,  Blast .  201,  202 

Lamps,  Hefner . 246 

Lamp,  Single  Filament  for  Galvanom¬ 
eter  . 348 

Lamps,  Kerosene . 240 

Lamps,  Projection . 241 

Lamp  Wicks . 452 

Lantern  Electrolysis  Apparatus  .  .  403 

Lantern  Slides,  Physics .  28 

Larynx  Phantom,  Model . 470 

Larynx  Models . 470 

Lead  Cylinder  with  Conical  Top  229 

Lead  Dishes  .  X . 432 

Lead  Shot . 229 

Lead  Sinker . 128 

Lead  Wire . 311 

Leaning  Tower . 100 

Leather  Belting,  round .  21 

LeClanche  Battery . 322 

Lecture  Table,  Biology . 444 

Lecture  Table  Clasps  .......  312 

Lecture  Table  Connectors  .  .  .  312,  313 
Lecture  Table  Galvanometers  .  338-341 

Lecture  Table  Hardware  Outfits  22,  23 
Lecture  Table  Rheostat  and  Resis¬ 
tance  Frame . 363 


Lecture  Table  Ring  Stand  ....  485 

Lecture  Tables .  4,  5 

Lenses .  258,  259 

Lenses,  Mounted .  259,  460 

Lens  Holders .  22,  245,  248 

Leslie’s  Cubes . 206 

Leveling  Screws .  16 

Leveling  Table  for  Charles  Law  Tube, 

Hall . 225 

Levels .  44 

Lever  and  Supporting  Table ....  127 

Lever  Clamps .  109 

Lever  Indicator .  94 

Levers .  109,  126,  127 

Lever  Screw  Compressor  Clamp  .  .  423 

Lever  Support,  Culler's . 105 

Leyden  Jar  Batteries . 303 

Leyden  Jars .  301,  303 

Leyden  Jars.  Resonant . 377 

Leyden  Jar  Dischargers  . 298 

Liebig’s  Condensers . 211,  425 

Life  Slide . 461 

Lifting  Magnets . 332 

Lift  Pumps . 140 

Light  Box .  255  . 

Lightning  Conductor . 302 

Lightning  Jars . 451 

Lightning  Plate . 301 

Lightning  Spiral  Tube . 301 

Light  Screens .  245,  248 

Lilliputian  Projection  Lamp  ....  241 

Lime  Water . 406 

Linear  Expansion  Apparatus  221-224 


CATALOGUE  OF  SCIENTIFIC  INSTRUMENTS 


503 


PAGE 


PAGE 


PAGE 


Linen  Tester .  259,  452 

Lines  of  Force  Apparatus . 280 

Liquid  Conduction  Tube . 208 

Liquid  Interrupters . 375 

Liquid  Interrupting  Induction  Coil 

374,  375 

Liquid  Level  Apparatus . 137 

Liquid  Level  Tubes . 137 

Liquid  Measures .  32 

Liquid  Pressure  Gauges . 133 

Liquid  Pressure  Tube,  loaded,  grad¬ 
uated,  F.  &  B . 135 

Liquid  Pressure  Tubes . 135 

Lissajous’  Curves  Apparatus.  .  .  .  193 

Liter  Blocks . 29,  30 

Liter  Cases .  30 

Liter  Measures .  32 

Litmus  Paper .  452,  471 

Litmus  Pencil . 452 

Loaded  Cylinder . 100 

Locomotive  Chart . 235 

Lodestones . 278 

Lodestone  Stirrup . 278 

Logarithm  Tables .  452  ,  487 

Low  Form  Bunsen  Burner . 200 

Low  Temperature  Thermometers  216 

Luminous  Cascade . 251 

Luminous  Leyden  Jar . 303 

Lummer-Brodhun  Photometer  .  .  .  246 

Lungs,  Models . 469 

Lycopodium  Powder  194 

Lyon's  Car . 103 


M 


Magdeburg  Hemispheres .  157 

Magnet  and  Friction  Rod  Support  279 
Magnet  and  Meter  Rod  Supports  .  281 

Magnet  Boards . 279 

Magnetic  Compasses .  286,  287 

Magnetic  Distribution  Apparatus.  .  283 

Magnetic  Fields  of  Force  Apparatus 

279,  280 

Magnetic  Induction  Coil . 329 

Magnetic  Needles,  mounted  ....  285 

Magnetic  Pole  Rotation  Apparatus .  282 
Magnetic  Rotating  Apparatus  ...  83 

Magnetic  Screens . 279 

Magnetized  Steel  Disc . 278 

Magneto . 395 

Magnetometers  .  . .  281,  282 

Magnetoscope . 282 

Magnets .  278,  279 

Magnets,  Floating . 279 

Magnets,  Molecular .  278,  279 

Magnet  Stirrup . 279 

Magnet  Supports . 279 

Magnifiers .  259  ,  452  ,  453 

Make  and  Break  Interrupter  .  .  .  372 

Manikins . 453 

Manometers . 155 

Manometer  Tubes . 133,  155 

Manometric  Flame  Apparatus  .  .  .  195 

Manometric  Flame  Capsule  ....  82 

Marine  Compass  . . 287 

Mariotte’s  Bottle . 136 

Marker  Clamp  and  Stylus  ....  95 

Mason's  Hygrometer . 166 

Material  for  Making  Slides  ....  463 

Mathematical  Models . 67,  68 

Mats,  Cork . 426 

Maximum  and  Minimum  Therrqome- 


Maximum  Density  of  Water  Appara 


tus . 225 

Maximum  Density  of  Water  Bulb  212 

Measures  of  Length . 31-37 

Measuring  Tapes .  34 

Mechanical  Equivalent  of  Heat  Ap¬ 
paratus  .  230,  231 

Mechanical  Equivalent  of  Heat  Tube  231 
Mechanical  Powers  Apparatus  .  109,  127 
Mechanical  Powers  Support,  Culler’s  105 
Mechanical  Powers,  Weights  for  62-63,  127 


Mechanical  Rotators . 21,  77 

Mechanical  Stage . 460 

Medicine  Droppers . 472 

Melting  Point  Tube . 212 

Mercury  Pendulum .  65 

Mercury  Pole  Changer . 319 

Mercury  Pumps .  151 

Mercury  Still . 482 

Mercury  Storage  Funnel . 146 

Mercury  Tube . 306 

Mercury  Well .  148 

Metalaphone . 185 

Metallic  Coated  Pith  Balls  ....  293 

Metallic  Thermometer . 213 


Metal  Snips . 478 

Metalurgical  Microscopes . 457 

Meteorological  Equipments  ....  169 

Meteorological  Thermometers  .  163-165 

Meter  Rod  Caliper  Arms .  37 

Meters,  Indicating .  474,  475 

Meter  Stick  Attachment,  T-Beam  .  26 

Meter  Stick  Clamps . 19,  26 

Meter  Stick,  Comparative .  31 

Meter  Sticks  .  .  31,  32 

Meter  Stick  Supports,  metal  ...  88 

Meter  Stick  with  Loop  for  String  .  88 

Metric  Chart .  29 

Metric  Rules . 32,  33 

Metronome .  66 

Mica  Condensers . 388 

Micrometer  Calipers . 35,  36 

Micrometer  Screw  Attachment,  T- 

Beam .  26 

Micrometer  Screws . 38,  39 

Microphone .  401 

Microscope,  Demonstration,  M.  & 

G . 266 

Microscope  Lamp . 460 

Microscope  Model . 266 

Microscope  Nosepieces . 459 

Microscopes .  454-458 

Microscopic  Slide  Labels . 452 

Microscopic  Slides  ...  461 ,  462,  463 

Microtome  Freezing  Attachment  .  .  466 

Microtome  Knife  Back . 466 

Microtome  Knife  Handle . 466 

Microtome  Knife  Strop . 466 

Microtome  Knives . 466 

Microtome  Ribbon  Carrier  ....  465 

Microtomes .  464,  465 

Milk  Dishes,  Aluminum . 432 

Milk  Pipettes . 468 

Milk  Preservatives . 468 

Milk  Test  Bottles . 468 

Milk  Testers .  467,  468 

Milk  Testing  Apparatus  .  .  .  467,  468 

Miller-Cowen  Attachment  for  Gilley 

Gramme  Machine . 393 

Miller  Lantern  Slides .  28 

Millimeter  Scale,  mounted  ....  95 

Minder’s  Manikin . 453 

Mineralite  Thermopiles . 219 

Minerals  and  Rocks . 469 

Miner’s  Compass . 286 

Minot’s  Slide  Cabinet . 461 

Mirror  Attachment  for  Torsion  Pen¬ 
dulum  .  92 

Mirrors . 249 

Mirror,  Scale  and  Support,  M.  G.  & 

B .  95 


Mirrors,  Concave  and  Convex, 

mounted . 244 

Mirrors  for  Lissajous’  Curves  ...  181 

Mirrors,  Galvanometer . 348 

Mirrors,  Interference . 272 

Mirrors,  Mounted .  22 

Mirrors,  Rotating . 82,  83 

Mixing  Cylinders  ...  429  .  447,  451 

Model,  Arch . 126 

Model,  Arc  Lamp . 404 

Model,  Bridge,  Davis’  ......  124 

Model,  Controller . 397 

Model,  Diving  Bell . 157 

Model,  Gas  Engine . 232 

Model,  Microscope . 266 

Model,  Screw . 119 

Models,  Crystal .  68 

Models,  Eye . 259 

Models,  Naturalistic . 175-178 

Models,  Physiological .  469,  470 

Models,  Pump . 140 

Models,  Sectional  of  Steam  Engine 

233—235 

Model,  Steam  Chest . 233 

Models,  Telescope . 266 

Models,  Turbine . 142 

Models,  Valve . 141 

Models,  Water  Wheel . 142 

Model,  Three  Phase  Current  Motor  399 

Model,  Wedge . 119 

Mohr’s  Burettes . 419 

Mohr’s  Pinchcocks . 423 

Mohr's  Pipettes . 472 

Molecular  Magnet  Model . 279 

Momentum  Apparatus .  90 

Monkey  Wrench . 405 

Monochromatic  Flame  Burner  .  .  .  240 

Morse's  Sympathetic  Vibration  Ap¬ 
paratus  . 183 

Mortar,  Electric . 302 

Mortars  . 470 


Motor-Dynamo  Demonstation  Ap¬ 
paratus  . 391 


Motor,  Electrostatic . 302 

Motor  Generators .  386,  390 

Motors,  A.  C.  and  D.  C . 396 

Motors  and  Dynamos  ....  389-397 

Motors,  Small .  389,  390 

Motors,  Water . 143 

Mounted  Transmission  of  Sound 

Tube . 185 

Mounted  Tuning  Forks  .  179,  181,  182 

Mounting  Board,  Barometer  .  .  .  160 

Mounting  Paper . 472 

Mounts,  Microscopic .  462,  463 

Mounts,  Specimen . 480 

Muencke’s  Aspirator .  153  ,  407 

Muffle  Furnaces .  440-442 

Muffles . 470 

Multiple  Image  Apparatus . 250 

Multiple  Range  Rotary  Meter  .  .  .  352 

Multiple  Range  Self-Cooling  Rectifier  385 

Museum  Jars . 451 


Mutual  Action  of  Parallel  Currents  283 


N 

National  School  Sonometer  ....  189 

Naturalistic  Models . 175-178 

Natural  Magnets . 278 

N.  &  F.  Apparatus  for  Optical  Disc  254 

Needle,  Inoculating . 470 

Needle  Holder,  Dissecting . 433 

Needles . 279 

Needles,  Dissecting . 433 

Nessler’s  Jars .  451,  470 

Nessler’s  Tubes . 491 

Net,  Faraday’s . .  300 

Nets,  Blower . 414 

Newton’s  Combination  Disc  ....  81 

Newton's  Rings . 273 

Nichol’s  Pascal's  Vase  Apparatus  134 

Nicholson's  Hydrometers . 131 

Nickel  and  Ammonium  Sulphate  403 

Nickel  Anode . 403 

Nickel  Crucibles . 427 

Nickel  Evaporating  Dishes  ....  431 

Nickel  Strip . 279 

Nickel  Suspension  Filaments  .  .  .  348 

Nicol’s  Prisms . 275 

Nipper . 405 

Nipple,  Brass . 156 

Nodon  Valve . 385 

Normal  Tuning  Forks .  180 

Normal  Weights .  58 

Nosepieces . 459 

O 

Odd  Angle  Glass  Prisms . 260 

Objectives,  Achromatic  ....  458,  459 

Oculars . 459 

Oersted's  Law  Apparatus . 327 

Oil  for  Air  Pumps . 150 

Oil-Sealed  Air  Pumps . 150 

Oil  Stone .  405,  471 

Oil  Testers . ••••••  471 

One  Ohm  Resistance,  M.  &  G.  354 

Opaque  Screen,  Black  and  White, 

with  Square  Opening,  F.  &  B.  248 
Opaque  Screen  with  Crossed  Opal- 

escent  Square  Opening,  F.  &  B.  248 

Opalescent  Screen . 245 

Optical  Bench  Clamps . •  17 

Optical  Benches .  244-248 

Optical  Bench  Outfits  ....  247,  248 
Optical  Disc  Accessories  .  .  .  251-254 

Optical  Disc  Glass  Parts  .  .  .  •  ■  255 

Optical  Discs .  252  255 

Optical  Light  Box . 255 

Optically  Plane  Mirror . 348 

Ores  and  Minerals . 4bJ 

Organ  Pipes . J®* 

Osborne’s  Electrolysis  Apparatus  402 

Osmosis  Apparatus .  75,  145 

Osmosis  Bulb . J’O 

Osmotic  Pressure  Tube . 140 

Outside  Calipers .  35 

Overflow  Can . 138 

Overflow  Pipettes . 4/2 

Ovens,  Drying . 435 

Oversleeves . 4  /  * 

"Oxone”  Cartridges . 440 

Oxygen  Gas  Generator .  445 

Ozone  Generator  Tube . 3// 


Packard’s  Electrolysis  Apparatus  . 
Packard’s  Falling  Body  Apparatus 


4(Xt 

101 


504 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


•  > 


PAGE 


PAGE 


PAGE 


Page  Motor  Apparatus  .......  395 

Palm  or  Pulse  Glass,  Franklin's  .  .  211 

Pans,  Agateware . 471 

Pan,  Dissecting . 433 

Paper,  Blackprint . 280 

Paper,  Blueprint . 280 

Paper  Brush . 301 

Paper,  Carbon  . 101 

Paper,  Coated  for  Vibrograph  .  .  .  191 

Paper  Condensers . 388 

Paper,  Cross  Section .  70,  101 

Paper,  Drying . 472 

Paper,  Filter . 437 

Paper,  Genus  Covers . 472 

Paper,  Litmus .  452  .  471 

Paper.  Mounting . 472 

Paper,  Pole  Test . 300 

Paper,  Touch . 207 

Paper,  various  kinds . 471 

Papin  Digestors . 209 

Parabolic  Reflectors .  186,  205 

Paraffine  Baths . 409 

Paraffine  Candles . 239 

Paraffine  Cube . 129 

Parallel  Current  Apparatus  ....  283 

Parallel  Current  Repulsion  Coils  .  .  329 

Parallel  Rule .  70 

Parallelogram  of  Force  Table  ...  98 

Paramagnetic  and  Diamagnetic 

Study  Apparatus . 333 

Paramagnetic  and  Diamagnetic  Sub¬ 
stances  . 279 

Parchment  Paper .  156,  471 

Parr's  Standard  Calorimeters  .  .  .  226 

Pascal’s  Vase  Apparatus.  .  .  .  134,  135 

Pencil  Compasses .  70 

Pencil,  Indelible . 471 

Pencil,  Litmus . 452 

Pendulum  Apparatus . 104 

Pendulum  Balls .  86 

Pendulum  Bobs,  Cylindrical  ....  104 

Pendulum  Clamp,  T.  &  H . 104 

Pendulum  Clamps .  20 

Pendulum,  Foucault's,  for  Rotator  .  79 

Pendulum,  Mercury .  65 

Pendulums . 104,  105 

Pendulums,  Compensating .  65 

Pendulums,  Seconds .  65 

Pendulum  Support,  Culler's  ....  105 

Pendulums,  Torsion . 92,  93 

Pendulum,  Y  or  Sand . 194 

Penfield  Goniometers .  41 

Periodic  Law  Chart . 422 

Petri  Dishes . 432 

Petri  Dish  Holder . 471 

Phenolphthalein  Solution . 406 

Phials,  Bologna .  73. 

Phosphor  Bronze  Filaments  ....  348 

Phosphorescent  Geissler  Tubes  .  .  .  306 

Phosphorescent  Mercury  Tube  .  .  .  306 

Phosphorous  Pentoxide . 156 

Photometers  and  Accessories  .  242-248 

Photometric  Outfits  ......  247,  248 

Photo  Trays . 488 

Physics  Direction  Sheets .  27 

Physics  Tables .  2,  3 

Physiological  Models .  469,  470 

Physiology  Microscope  Slides  .  462,  463 

Piano  Wire . 199,  311 

Pickering  Polariscope . 274 

Picture  Wire . 311 

Pilz  Manikins . .  .  .  .  453 

Pinchcocks . 423 

Pin  Holder . 248 

Pin  Hole  Camera . 242 

Pipes,  Clay . 471 

Pipestem  Triangles . 488 

Pipettes,  Acid . 468 

Pipettes,  all  kinds . 472 

Pipettes,  Automatic . 468 

Pipettes,  Graduated . 406 

Pipette  Stand  . . 472 

Pipette  Support . 484 

Pins,  Insect . 471 

Pitch  Gauges . 405 

Pith . 466 

Pith  Balls . 293 

Pith  Ball  Klectrometers . 293 

Pith  Ball  Electroscopes . 293 

Pith  Images . 300 

Plane . 405 

Plane  Mirrors . 249 

Plano-Convex  Lenses .  258,  259 

Plant  Press . 472 

Plate  Base,  Andrews’ .  12 

Plate,  Lightning . 301 

Plate,  Colored  Glass . 267 

Plates,  Dessicator . 430 

Plates,  Filter . 437 


Plates,  Flush .  12 

Plates,  Glass . 472 

Plates,  Image . 300 

Plates,  Interference  of  Light  .  .  .  273 

Plates,  various  kinds . 472 

Plates  with  Projecting  Needles,  Hall  249 

Platform  Balances . 54,  55 

Platform  Counter  Scale .  54 

Platforms .  15 

Platinum  Ware . 473 

Platinum  Wire . 311,  473 

Pliers . 405 

Pliers,  Side  Cutting . 474 

Plotting  Scales . 33,  42 

Plug  Pole  Changer . 319 

Plumb  Bobs .  44 

Plummets,  Specific  Gravity  ....  130 

Plunge  Batteries .  323,  324 

Pneumatic  Troughs . 489 

Pocket  Aneroid  Barometers  ....  162 

Pocket  Compasses,  Magnetic.  .  286,  287 

Pocket  Levels .  44 

Pocket  Magnifiers .  452,  453 

Pocket  Measuring  Tapes .  34 

Pocket  Spectroscope . 269 

Pohl’s  Commutator . 319 

Point  Switches . 316 

Polariscopes . 274 

Polariscope  Specimens . 276 

Polarization  Study  Apparatus  .  .  .  274 

Polarized  Light  Accessories  ....  276 

Polarized  Light  Attachments.  .  .  .  254 

Pole  Changers . 319 

Pole  Test  Paper . 300 

Policemen,  Rubber . 477 

Polyprisms .  262,  263 

Porcelain  Base  Switches . 316 

Porcelain  Beakers . 413 

Porcelain  Casseroles . 421 

Porcelain  Combustion  Boats  ....  425 

Porcelain  Crucibles .  427-429 

Porcelain  Evaporating  Dishes  .  .  .  431 

Porcelain  Funnels . 439 

Porcelain  Mortars . 470 

Porcelain  Plates .  472 

Porcelain  Retorts . 476 

Porcelain  Spoons . 479 

Porcelain  Tube,  F.  &  B . 313 

Porcelain  Tubing . 492 

Porosity  Demonstration  Apparatus  .  72 

Porous  Cups .  429,  474 

Porte  Lumieres . 239 

Portraits  of  Scientists .  28 

Potash  Bulbs . 419 

Potassium  Cyanide . 403 

Potential  Bar . 289 

Practical  Physics  Apparatus  .  .  121-127 

Pratt  Institute  Applied  Physics  Ap¬ 
paratus  .  121-127 

Pratt  Institute  Inclined  Plane  .  117,  121 
Pratt  Institute  Index  of  Refraction 

Apparatus . 257 

Precision  Weights .  59 

Preparation  Dishes .  432,  481 

Primary  and  Secondary  Coils  .  .  .  372 

Prince  Rupert  Drops .  73 

Principal  Focus  Box,  Culler's  .  .  .  248 

Prism,  Equilateral,  M.  &  G.  .  .  .  256 

Prism  Gratings . 273 

Prisms .  260-263  ,  271 

Prisms,  Foucault’s . 275 

Prisms,  Mounted . 263 

Prisms,  Nicol's . 275 

Prisms,  Triangular,  wood .  94 

Preservatives,  Milk . 468 

Press,  Plant . 472 

Presses,  Cork . 426 

Pressure  of  Gas  Apparatus  ....  146 

Pressure  Gauge  for  Apparatus  A .  .  203 

Pressure  Gauge  Projection  Holder  .  133 

Pressure  Gauges .  133,  146,  155 

Pressure  Syringes . 132 

Pressure  Tubes . 133,  155 

Pressure  U-Tubes . 135 

Projection  Apparatus . 277 

Projection  Apparatus,  Magnetic 

r«!  Lines  of  Force . 280 

Projection  Electroscopes  .  .  .  294,  295 

Projection  Frequency  Indicator.  .  .  398 

Projection  Galvanometer . 340 

Projection  Holder' . 133 

Projection  Lamps . 241 

Proof  Plane . 298 

Protectors,  X-Ray  Tube . 310 

Protractors,  Instrument  for  Making  43 
Protractor  Rule  and  Square  ....  40 

Protractors . 40-42 

Protractor  Triangles .  40 

Psychrometer . 166 


Pulley  Assortments . Ill 

Pulley  Attachment,  T-Beam  ....  26 

Pulley  Cord  •  •  Ill 

Pulley  Demonstration  Apparatus  114,  115 
Pulley,  Drive,  for  Round  Belt  ...  78 

Pulley  Hoists,  Differential . 113 

Pulley  in  Frame . 117 

Pulley  Rope . 112 

Pulleys . 110-117 

Pulleys,  mounted .  22 

Pulley  Support,  Culler’s . 105 

Pumice . 403 

Pump,  Carboy . 474 

Pump  Models . 140 

Pump  Oil  and  Can . 156 

Pump  Plates . 151 

Pumps,  Air . 149-153 

Punch . 405 

Push  Buttons . 316 

Pyknometers  .  .  •■ . 130,  418 

Pyrex  Glassware . 494 

Pyrex  Glass  Beakers . 412 

Pyrometers .  220,  474,  475 

Pyrometer  Tubes . 475 


Q 


Quadrant  Electrometer  ....  296,  302 

Quadrant  Protractors .  43 

Quart  Measure .  32 

Quartz  Prisms  .  .  . . 261 

Quick  Acting  Clamp . 423 

Quincke's  Tubes . 188 


R 


Racks  for  Bottles . 444 

Radiation  Apparatus . 302 

Radiation  Screens . 206 

Radio  Active  Substances . 297 

Radio  Electroscopes .  294-296 

Radiographs . 476 

Radiometers . 204 

Radio  Micrometer . 345 

Rain  Gauges . 167 

Rams,  Hydraulic . 139 

Ratio  Box . 360 

Rayboum  Quadrant  Electrometer  .  296 

Razors,  Section . 433 

Razor  Strop . 466 

Reaction  Gas  and  Flame  Wheel  .  .  141 

Reaction  of  Gas  Apparatus  ....  141 

Reaction  of  Liquids  Apparatus  .  .  141* 

Reaction  Wheel,  Acoustic . 197 

Reading  Lens .  259,  452 

Reagent  Bottles . 416,  417 

Reagents  and  Stains . 497 

Recalescent  Outfit . 475 

Receivers,  Retort . 476 

Receivers,  Telephone . 400 

Receivers,  Wireless  Head  Band  .  .  384 

Recording  Barometer . 162 

Recording  Drums . 192 

Recording  Thermometers . 165 

Recording  Tuning  Fork . 181 

Record(Sheets,  Kymograph  ....  192 

Rectifiers.  Electrolytic . 385 

Reflecting  Level .  44 

Reflecting  Sextants . 267 

Reflection  Apparatus . 250 

Reflection  of  Heat  Apparatus  .  .  .  205 

Reflection  of  Sound  Apparatus.  .  .  186 

Reflectors,  Parabolic  .....  186,  205 

Refraction  Tank  for  Optical  Disc  .  254 

Refraction  Tanks .  256,  257 

Registering  Anemometers . 168 

Registering  Rain  Gauge . 167 

Regulating  Rheostats .  363.  364 

Regulator,  Gas  Pressure . 446 

Regulators,  Gas . 446 

Relay,  Telegraph . .  400 

Relief  Models . 175-178 

Repulsion  Coils . 329 

Resin . 199 

Resistance  Board . •  355 

Resistance  Boxes .  357-362 

Resistance  Coils .  354-356 

Resistance  Frame . 363 

Resistances,  Spool . 354 

Resistances,  Standard .  355,  356 

Resistance  Units .  363  ,  365 

Resonance  Apparatus . 190,  191 

Resonance  Tubes . 190,  191 

Resonant  Leyden  Jars . 377 

Resonators . 197 

Respiration  Models . 469 

Retorts . 476 


CATALOGUE  OF  SCIENTIFIC  INSTRUMENTS 


505 


PAGE 

Retort  Stands . 485 

Reversible  Pendulums . 104,  105 

Reversing  Key  .  . . 318 

Revolving  Disc . 302 

Revolving  Dustproof  Nose-Pieces  .  459 

Revolving  Mirror . 82,  83 

Rheochords . 355 

Rheostats .  363,  364 

Ribbon  Carrier,  Microtome  ...  465 

Richards'  Aspirators .  153  ,  407 

Richards’  Blast  Apparatus  ....  413 

Richmond’s  Slide  Rule . 468 

Rider  Block . 109 

Rider  Weights .  59 

Right  Angle  Clamps  ....  16.  17,  19 

Right  Angle  Prisms .  260-263 

Riker  Mounts . 480 

Ring  Burners . 420 

Rings,  Ring  Stand . 476 

Ring  Stand  Rings . 476 

Ring  Stands . 485 

Rintoul’s  Dynamometer . 57 

Rip  Saw . 405 

Ritchie  Photometer . 242 

Ritchie  Reversing  Key . 319 

Rocks  and  Minerals . 469 

Rods  for  Torsion . 92,  94 

Rods,  Friction . 289 

Rods,  Glass,  Fused  Silica  .  v  .  .  .  477 

Rods,  Support . :  .  .  10 

Rod,  Steel,  M.  G.  &  B .  94 

Rod  V-Clamp  Attachment,  T-Beam  26 

Rod,  Waterproof . 129 

Roentgen  Ray  Apparatus  .  .  .  309,  310 
Rollers,  Inclined  Plane  .  .  .  .  117,  121 

Roof  Truss .  123 

Rope,  Pulley . 112 

Rose’s  Crucible  .• . 429 

Rotary  Compressors .  152 

Rotary  Converters . 386 

Rotary  Field  Apparatus  for  A.  C  .  .  399 

Rotary  Meter  for  D.  C . 352 

Rotary  Microtome .  464,  465 

Rotating  Mirrors . 82,  83 

Rotator  Globe  and  Dish .  80 

Rotators . 21,  77,  78 

Rotators,  Geissler  Tube . 307 

Rouge . 403 

Rouge  Cloth . 403 

Round  Bases .  11 

Round  File . 437 

Round  Leather  Belt .  21 

Royal  Worcester  Porcelain  Ware  495 

Rubber  Bags .  156,  445 

Rubber  Bands .  477 

Rubber  Base  Switches.  ......  316 

Rubber  Cord . 108 

Rubber  Cord  for  Inertia  Experiment, 

Hall . 118 

Rubber  Dam  or  Thin  Sheet  .  .  156,  477 

Rubber  Discs  for  Blowers  .  .  .  414,  477 

Rubber  Friction  Rod . .  .  289 

Rubber  Gaskets  for  Alundum  Cru¬ 
cibles  . 428 

Rubber  Gaskets  for  Filter  Cones  437 

Rubber  Hammers .  179 

Rubber  Policemen . 477 

Rubbers,  Friction  Rod . 289 

Rubber  Spatula . 479 

Rubber  Stoppers . 478 

Rubber  Tubing .  200,  477 

Rubber  Tubing  for  Gooch  Crucibles  429 

Ruhmkorff  Cods . 373 

Ruled  Cardboard  Strip.  F.  &  B.  266 

Rule,  Parallel .  70 

Rules . 32,  33 

Rumford’s  Photometer . 243 

Rutherford’s  Prisms .  261,  271 


S 


Saccharometer . 

. 478 

Safety  Lamp,  Davy’s  .  . 

. 208 

Safetv  Tubes . 

. 491 

St.  Louis  Motor  .  .  .  . 

. 391 

Sand  Apparatus  .... 

. 302 

Sand  Baths . 

. 409 

Sand,  Chladni's  Plate  .  . 

. 194 

Sand  Crucibles . 

. 429 

Sand  Paper  . 

. 471 

Sand  Pendulum  .... 

. 194 

Savart's  Wheels  .... 

.  81 

Saws . 

. 405 

Scale  Pans . 

...  94,  109 

Scales  . 

Scalpels . 

. 433 

Scheibler’s  Dessicators 

. 430 

Scissors . 

. 478 

PAGE 

Shellbach’s  Burettes . 419 

Schellbach’s  Support .  484 

Scissors,  Dissecting . 433 

Scoop,  Horn . 478 

Screen,  Electric . 299 

Screen  Holders . .  .  245,  248 

Screens,  Absorption  and  Radiation  206 

Screens,  Magnetic . 279 

Screens,  Optical  Bench  ....  245,  248 

Screen  with  Apertures . 245 

Screen  with  Vertical  Slit . 245 

Screw  Compressor  Clamps  ....  423 

Screw,  Cork . 426 

Screw  Drivers . 405 

Screw  Gauge .  39 

Screw  Jack  with  Wheel,  Base  and 

Bar . 127 

Sealing  Wax . 493 

Seasonal  Twilight  Chart .  172 

Secondary  Basic  Attachment,  T- 

Beam .  26 

Secondary  Supports .  13 

Second  Law  of  Motion  Apparatus  .  .  90 

Seconds  Pendulums .  65 

Section  Lifters . 433 

Section  Razors . 433 

Selenium  Cells . 401 

Self  Induction  Apparatus . 387 

Self  Induction  Coils . 387 

Self  Leveling  D’ Arson  val  Galva¬ 
nometer .  344,  345 

Self  Registering  Thermometers  .  163,  164 

Semi-blast  Wynne  Burner . 201 

Separatory  Funnels . 439 

Set  Square,  Universal .  70 

Seven-in-One  Apparatus . 138 

Sextants . 267 

Sharpener,  Cork  Borer . 426 

Shear  Legs . 122 

Shears . 478 

Shears,  Metal . 405 

Sheet  Cork . 426 

Sheeting,  Rubber . 156 

Shell  Vials . 492 

Shelters,  Instrument . 169 

Shelves,  Digesting . 430 

Shocking  Handles . 301 

Shocking  Handles  and  Cords  .  .  .  298 

S-Hook .  55 

Short  Circuit  Keys . 318 

Shot,  Lead,  Copper,  Aluminum  .  .  229 

Show  Jars,  Inverted . 451 

Shredder  and  Shave,  Ice . 204 

Shunts . 347 

Sieves . 478 

Sifter,  Filings . 280 

Sight  Compasses,  Magnetic  ....  287 

Silica  Beakers . 413 

Silica  Capsules . 421 

Silica  Casseroles  . 421 

Silica  Combustion  Boats . 425 

Silica  Crucibles . 428 

Silica  Dishes . 432 

Silica  Evaporating  Dishes . 431 

Silicon  Detector . 384 

Silk  Exciting  Pad . 289 

Silver  Anode . 403 

Silver  Chloride . 403 

Singing  Flame  Apparatus . 183 

Single  Contact  Key . 317 

Single  Plug  Switch . 318 

Single  Rod  Attachment,  T-Beam  .  26 

Sinker,  Lead . 128 

Siphons .  137,  479 

Siren  Discs . 81,  82 

Sirens,  Caignard-La-Tour . 188 

Six’s  M.  &  M.  Thermometer  ...  163 

Skidmore  Battery . 320 

Skin  Model . 469 

Skins,  Birds' . 413 

Skull  and  Brains,  Model  of  ...  .  470 

Slide  Boxes . 461 

Slide  Cabinet . 461 

Slide,  Holman’s  Life . 461 

Slide  Making  Material . 463 

Slide  Rule,  Richmond’s  for  Milk  468 

Slide  Rules .  42 

Slides,  Microscopic . 461 

Slides,  Prepared  Microscopic  462,  463 

Slide  Wire  Bridges .  368,  369 

Sliding  Caliper .  36 

Sling  Psychrometer . 166 

Slit  Diaphragm . 239 

Slope  Level .  44 

Smith  School  Squares .  40 

Smoke  Condensation  Apparatus  .  .  301 

Snips,  Metal . 405 

Sodium  Capsule . 479 

Sodium  Spoon . 479 


PAGE 

Soft  Iron  Bar . 279 

Soft  Iron  Horseshoe  Core,  M.  G.  & 

0  B . 279 

Soil  Sieves . 478 

Soil  Thermometer .  164 

Solar  Calculator . 173,  174 

Solder . 479 

Soldering  Copper . 1  .  .  479 

Soldering  Fluid . 479 

Soldering  Iron,  Electric . 436 

Soldering  Iron  Heaters . 479 

Soldering  Outfits . 479 

Soldering  Paste . 479 

Solenoid  Magnet . 331 

Solenoid  with  Movable  Coil  ....  331 

Solid  Alcohol . 406 

Sonograph . 196 

Sonometer  Attachment,  M.  G.  &  B.  117 

Sonometers .  189 

Sonometer  Wires . 189 

Sounder  Parts,  Telegraph . 400 

Sounder,  Telegraph . 400 

Soun4  Lens .  187 

Soxhlet’s  Copper  Condensers.  .  .  .  425 

Soxhlet’s  Extraction  Apparatus  .  .  436 

Soxhlet’s  Extraction  Tubes  ....  436 

Spark  Gaps,  Wireless . 383 

Spatulas . 479 

Spatulas,  Platinum . 473 

Specific  Gravity  Apparatus  .  .  128-131 

Specific  Gravity  Apparatus  for  gases  72 
Specific  Gravity  Balances  .  .  .  .  53.  54 
Specific  Gravity  Bottles  ....  130,  418 
Specific  Gravity  Plummets  ....  130 

Specific  Gravity  Specimens  .  .  128,  129 
Specific  Heat  Apparatus,  Tyndall's  229 

Specimen  Bottles . 418 

Specimen  Jars . 451 

Specimen  Mounts .  480 

Specimens,  Polariscope . 276 

Specimens,  Slide  Making . 463 

Specimens,  Zoological . 480 

Spectral  Apparatus  and  Goniometer  269 

Spectrometer . 270 

Spectroscopes .  269,  270 

Spectroscopic  Prisms .  261,  271 

Spectrum  Charts . 267 

Spectrum  Tubes . 271 

Speed  and  Power  Rotator .  78 

Speed  Indicator  for  Rotator  ....  79 

Speed  Indicators .  67 

Speedometers .  67 

■  Spheres,  all  kinds .  86 

Spherometers .  38 

Spindle  and  Clamp .  21 

‘‘Spinning  Tops” .  85 

Spiral  Hygrometer . 166 

Spiral  Spring . 108 

Spirometer .  138 

Splints . 479 

Splint  Ring  Pole  Charger . 319 

Sponges . 479 

Spool  Resistances . 354 

Spoons . 479 

Spreader  for  Trip  Scale .  55 

Spring  and  Weight  Holder,  M.  G.  & 

B .  95 

Spring  Balances . 56,  57 

Spring  Magnetometer . 282 

•Spring  Punch . 405 

Squares . 40-42 

Staining  Box,  Glass . 461 

Staining  Jar  :  .  .  . . 451 

Staining  Jar,  Coplin's . 451 

Stains  and  Reagents . 497 

Standard  Candle . 246 

Standard  Cells . 325 

Standard  Meter .  34 

Standard  Resistances .  355,  356 

Standard  Sources  of  Light  ....  246 

Standard  Thermometers . 215 

Stand,  Electrostatic . 301 

Stands,  Insulating . 297 

Stands,  X-Ray  Tube . 310 

Stand  Tops .  14 

Stand  Tubes .  13 

Stand,  Universal .  87 

Star,  Burner . 420 

Star  Chart . 172 

Static  Electrometers . 293 

Steam  Boiler  and  Engine . 237 

Steam  Boilers .  203,  238 

Steam  and  Electric  Power  Plant  .  238 

Steam  Chest  Model .  233 

Steam  Engine  Models  ....  233-235 

Steam  Engines .  233-238 

Steam  Power  Plants .  237,  238 

Steam  Traps . 204 

Steam  Water  Baths . 411 


L.  E.  KNOTT  APPARATUS  CO 


BOSTON 


506 


•  > 


PAGE 

Steel  Filings  in  Glass  Tube  ....  278 

Steel  Mortar . 470 

Steel  Rules .  33 

Steel  Spatulas . 479 

Steel  Suspension  Filaments  ....  348 

Steelyard . 109 

Steelyard,  Laboratory . 126 

Stencil . 481 

Stencil  Cut-Outs . 481 

Stender  Dishes .  432,  481 

Sterilizers . 481 

Stills . 210,  482 

Stirrer  for  Calorimeter . 227 

Stirrup,  Magnet . 279 

Stone’s  Tension  Clamps .  97 

Stone’s  Tension  Clamps,  T-Beam  .  26 

Stools,  Insulating . 297 

Stop  Clock .  66 

Stopcock,  Gas . 445 

Stopcocks,  Brass . 156 

Stopcocks,  Glass . 483 

Stoppers.  Rubber . 478 

Stop  Watch .  66 

Storage  Batteries . 325 

Storage  Battery  Hydrometers  .  .  .  448 

Storage  Jars . 451 

Storage  Tanks,  Air . 153 

Stove,  Electric . 436 

Stoves .  201,  483  ,  484 

Straight  Edge  Rule .  33 

Streak  Plate . 472 

Stretching  Block  with  Pillar  and 

Binding  Post .  95 

Strip  with  Two  Hooks,  T.  &  H.  115 

Strop . 466 

Students'  Optical  Disc . 255 

Students’  Table,  Biology . 444 

Stylus  and  Fixative . 191 

Substage  Condensers . 459 

Substances,  Radio  Active . 297 

Sulphuric  Acid  Cryophorous  ....  212 

Sulphur  Specimen . 128 

Sun  Dial .  66 

Sun  Dial  and  Compass . 287 

Sunlight  Projectors . 239 

Sun  Spectrum  Chart . 267 

Support  Blocks,  Wood,  M.  G.  &  B.  94 

Support  Board  for  Composition  of 

Forces .  97 

Support,  Brass . 129 

Supporting  Boards,  Magnet  ....  279 

Support,  Magnet  and  Friction  Rod.  279 

Support  Rods .  10 

Supports . 11-16 

Supports,  Trip  Scale .  55 

Supports,  Tube . 403 

Supports,  various  kinds  ....  484-486 

Surface  Tension  Apparatus  .  .  .  73-76 

Suspension  Filaments,  Galvanometer  348 
Swiftest  Descent  Apparatus  ....  106 

Switches,  Electrical . 316 


Swivel  Post  Attachment,  T-Beam  26 

Sympathetic  Tuning  Forks . 182 

Sympathetic  Vibration  Apparatus  .  183 

Syracuse  Watch  Glasses . 493 

Syringe,  Hyperdermic . 486 

Syringes,  Pressure . 132 


T 

Table,  Aquarium . 406 

Table  Clamps  ....  13,  16,  21,  25,  26 
Table  for  Parallelogram  of  Forces  .  98 

Tables,  Biology . 444 

Tables,  Laboratory . 2-5,  8,  444 


Table,  Microtome . 464 

Table  Top  on  Rod . 245 

Tablets,  Composite  Test,  for  Milk  .  468 

Table,  Warming . 466 

Tackle  Blocks .  112 

Tangent  Galvanometers  ....  335,  336 

Tangent  Scale .  43 

Tank,  Aquarium . 406 

Tanks,  Air  Storage . 153 

Tantalus  Cup . 137 

Tap  and  Die  Set . 405 

Taper  Gauge,  Inside .  39 

Taper  Gauge,  Outside .  39 

Tapering  Zinc  Element,  T.  &  H.  .  320 

Tapers,  Wax . 493 

Tapes,  Measuring .  34 

T-Beam  Basic  Tank . 140 

T-Beam  Clamps  and  Attachments  24-26 

T-Beam  Water  Pumps . 140 

Teeth  Model . 469 

Telegraph  Instruments . 400 


PAGE 

Telegraph  Key  Parts . 400 

Telegraph  Sounder  Parts . 400 

Telephone,  Battery  Call . 401 

Telephone  Receiver . 400 

Telephone  Transmitter . 400 

Telephonic  Microphone . 401 

Telescope  and  Scale . 349 

Telescope  Clamp .  21 

Telescope  for  Radio  Active  Work  .  295 

Telescope  Models . 266 

Telescopes .  264-266 

Tellurian . 170 

Temperature  Coils . 354 

Tenacula . 433 

Tensile  Strength  of  Wires  Apparatus  96 

Tension  Clamps,  Stone’s .  97 

Terrestrial  Telescope  Model  ....  266 

Tesla  Motor . 399 

Test  Glasses .  446  ,  487 

Test  Tube  Basket . 487 

Test  Tube  Brushes . 419 

Test  Tube  Clamps . 423 

Test  Tubes,  all  kinds . 487 

Test  Tube  Supports . 486 

Theater  Cable . 311 

Thermit  Reaction  Apparatus.  .  .  .  487 

Thermo-Couples . 475 

Thermo-Electric  Batteries . 220 

Thermographs .  165 

Thermograph  Charts . 165 

Thermometer,  Dairy . 468 

Thermometers,  all  kinds  .  .  .  213-218 

Thermometer,  Soil .  164 

Thermometers,  Maximum  and  Min¬ 
imum  .  163,  164 

Thermometers,  Meteorological  .  163-165 

Thermometers,  Recording . 165 

Thermopiles . 219 

Thermoscopes . 217 

Thimbles,  Extraction . 436 

4Q1 

Thousand  Ohm  Resistance,'  M.  &  G.  354 

Thorpe  Gauge . 229 

Threaded  Hook . 120 

Three  Phase  Current  Motor  Model  399 

Three  Rod  Attachment,  T-Beam  .  26 

Time  Marker .  192 

Tin  Foil .  293,  487 

Tip,  Burner . 420 

Toepler-Holtz  Machines  ....  290.  291 

Tongs,  Crucible . 429 

Tool  Cabinet  and  Tools . 405 

Tool  Holders . 405 

Tools . 405 

Torrentium  Oil . 150 

Torricellian  Law  Apparatus  ....  136 

Torsion  Apparatus . 91-93 

Torsion  of  Beams  Apparatus.  .  .  91,  92 

Torsion  of  Beams  Attachments,  T- 

Beam .  26 

Torsion  Pendulums . 92,  93 

Torso  Model . 470 

Total  Reflection  Apparatus  ....  251 

Total  Reflection  Prisms  .  .  260-263,  271 

Touch  Paper . 207 

Tourmaline  Tongs . 275 

Transformer,  Demonstration  ....  370 

Transformer,  Dissectible . 371 

Transformers,  Wireless . 383 

Transformers,  Wireless  Oscillating  .  383 

Translucent  Screen . 245 

Transmission  Diffraction  Gratings  .  273 

Transmission  of  Sound  Tube, 

mounted . 185 

Transmitter,  Telephone . 400 

Traps,  Steam  or  Water . 204 

Trays . 488 

Tray,  Ice . 204 

Trevelyan’s  Rocker . 198 

Triangle  Demonstration  Apparatus  68 

Triangle  Holders,  Platinum  ....  473 

Triangles,  Platinum . 473 

Triangles,  various  kinds  .  .  .  40,  70,  488 

Triangular  File . '.  .  .  437 

Triple  Beam  Balance .  54 

Triple  Connectors . 315 

Triple  Tandem  Pulleys . 112 

Tripod  Bases .  11 

Tripod,  Burner . 420 

Tripod  Magnifier . 452 

Tripod,  Rod,  Clamp  and  Holder,  M. 

1  G.  &  B .  148 

Tripods,  various  kinds . 489 

Tripoli . 403 

Trip  Scales .  55 

Trip  Scale  Supports .  55 

Troughs,  Absorption . 272 

Troughs,  Glass . 262 

Troughs,  Pneumatic . 489 


PAGE 


Trough,  Wave . 108 

Trowbridge  Galvanometer . 334 

Troy  Weights .  61 

Trumpet . 187 

Trunk  Model . 470 

Trusses .  123 

T-Square .  70 

T-Tubes . 490 

Tube,  Beveled  Glass,  T.  &  H.  .  .  209 

Tube,  Boiling  Point  of  Alcohol,  M. 

&  G . 209 

Tube,  Brush . 419 

Tube,  Burner . 420 

Tube  Clamp .  19 

Tube  Cutters,  Glass  .......  447 

Tube  Furnaces .  440,  441,  443 

Tube  Gauge .  39 

Tube,  Hopkins’  Forked . 188 

Tube,  Lightning  Spiral . 301 

Tube,  Manometer . 133,  155 

Tube,  Mechanical  Equivalentof  Heat  231 

Tube,  Melting  Point . 212 

Tube,  Ozone . 377 

Tubephone . 185 

Tubes,  all  kinds .  489-491 

Tubes,  Arsenic . 407 

Tubes,  Barometer .  148 

Tubes,  Cathode  Ray  or  Vacuum  308  ,  309 

Tubes,  Charles  Law . 225 

Tubes,  Crooke’s .  308,  309 

Tubes,  Extraction,  Soxhlet’s  ....  436 

Tubes,  Fractional  Distillation  .  .  .  435 

Tubes,  Gas  Measuring . 446 

Tubes,  Gas  Sample . 445 

Tubes,  Geissler .  305-308 

Tubes,  Liquid  Level . 137 

Tubes,  Liquid  Pressure . 135 

Tubes,  Pressure.  133,  155 

Tubes,  Pyrometer . 475 

Tubes,  Quincke’s  Interference  .  .  .  188 

Tubes,  Resonance . 190,  191 

Tubes,  Spectrum . 271 

Tube  Supports . 403 

Tubes,  Vapor  Tension . 209 

Tubes,  Waterman’s  Charles  Law  .  225 

Tubes,  X-Ray . 309 

Tube,  Tyndall’s  Sound . 198 

Tube,  Vapor  Pressure . 209 

Tube,  Volume  Coefficient,  M.  G.  &  B.  225 

Tubing,  Alundum . 492 

Tubing,  Fused  Silica . 489 

Tubing,  Glass .  491 

Tubing,  Glass  Combustion  ....  492 

Tubing,  Porcelain . 492 

Tubing  Rubber . 200 

Tubing,  Vacuum . 156 

Tumeric  Paper .  471,  492 

Tuning  Coil . 384 

Tuning  Fork  Apparatus . 191 

Tuning  Forks . 179-182 

Tuning  Forks,  Unadjusted  .  .  181,  191 

Tuning  Forks,  Sympathetic  ....  182 

Tuning  Fork,  Vibrograph . 191 

Turbines,  Water . 142 

Turn  Table . 461 

Turrets,  Gas . 445 

Twilight  Chart . 172 

Two-part  Iron  Armature,  T.  &  H.  279 
Tyndall’s  Heat  Attachment  for  Ro¬ 
tator  .  80 

Tyndall’s  Sound  Tube . 198 

Tyndall’s  Specific  Heat  Apparatus  229 


U 

Unadjusted  Cast  Iron  Weights  .  63,  127 


Unadjusted  Tuning  Forks  .  .  .  181,  191 
Unequally  Evacuated  Geissler  Tubes  307 

Ungraduated  Thermometer . 213 

Uniform  Pressure  Syringes  ....  132 

Uni-Polar  High  Frequency  Coil  .  .  378 

Universal  Holder .  18 

Universal  Lecture  Table  Galvanome¬ 
ter  .  338,  339 

Universal  Pulleys . 113 

Universal  Stand . 87 

Universal  Stand,  Electrostatic  .  .  .  301 

Upward  Pressure  Apparatus  .  .  134,  135 

U-Shaped  Magnet . 278 

U-Shaped  Wire  Supporting  Hook, 

T.&H .  109 

U-Tubes,  Pressure . 135 


V 

Vacuum  Gauges .  146 

Vacuum  Pumps  .  .  149-153 


CATALOGUE  OF  SCIENTIFIC  INSTRUMENTS 


507 


PACE 


Vacuum  Tubes .  308  ,  309 

Vacuum  Tubing .  156 

Valve  Models . 141 

Valve  Regulator .  80 

Vapor  Pressure  Tube . 209 

Vapor  Tension  Apparatus . 209 

Vapor  Tension  Tubes . 209 

Vasculum .  492 

Vase  Shape  Beaker . 412 

Vegetable  Parchment . 156 

Velocity  of  Sound  Apparatus  .  .  .  199 

Vernier  Arc  Model .  31 

Vernier  Caliper  Model .  37 

Vernier  Calipers . 36,  37 

Vernier  CaKper  Strip .  31 

Vernier  Models .  31 

Vertical  Index  Block . 249 

Vertical  Laminated  Magnet  Galva¬ 
nometer  . 343 

Vertical  Luminators . 460 

Vials . 492 

Vibration  Apparatus  for  Sound  .  .  198 

Vibration  Frequency  Apparatus  .  .  191 

Vibration  of  Rod  Apparatus  .  .  198 

Vibrating  Spiral  Apparatus  ....  283 

Vibrograph . 191 

Vibrograph  Tuning  Fork . 191 

Vinegar  Tube . 491 

Viscosimeter . 493 

Viscosity  Apparatus .  72 

Vise  Clamp  for  Bench  .......  90 

Vises . 493 

Volt-Ammeters . 353 

Voltmeters .  350-353 

Volume  Coefficient  Tube.  M.  G.  &  B.  225 

Volumetric  Flasks . 439 

Volumetric  Pipettes . 472 

Von  Nardroff  Color  Apparatus  .  .  268 

Vulcanite  Friction  Rod . 289 


W 

Wall  Bracket,  Galvanometer  .  .  .  346 

Wall  D’Arsonval  Galvanometer  .  .  346 

Wall  Stand .  15 

Warming  Table . 466 

Washers,  Leather . 156 

Washing  Bottles . 418 

Waste  Jars . 451 

Watch  Glasses . 493 


PACE 

Watch  Springs . 493 

Water  Baths . 410,  411 

Water  Batteries .  297,  324 

Water  Faucets .  9 

Water  Friction  in  Pipes . 141 

Water  Hammers . 156 

Water  Heater . 493 

Water  Heater,  Electric . 436 

Water  Lenses . 259 

Waterman's  Charles  Law  Tubes  .  .  225 

Water  Motors .  143 

Water  Stills . 210,  482 

Water  Thermometer . 225 

Water  Traps . 204 

Water  Turbines . 142 

Water  Wave  Apparatus . 108 

Water  Wheel  Model . 142 

Watt’s  Governor .  80 

Wave  Motion  Apparatus  .  .  .  107,  108 

Wave  Trough . 108 

Wax  Friction  Rod . 289 

Wax,  Sealing . 493 

Wax  Tapers . 493 

Weather  Bureau  Barometer  ....  160 

Weather  Bureau  Hygrometers  .  166,  167 
Weather  Bureau  M .  &  M .  Thermome¬ 
ters  .  163,  164 

Wedges .  119 

Wedge  Shape  Troughs  . 262 

Weighing  Bottles . 418 

Weight  Hangers .  62,  63,  127 

Weights . 58-63 

Weinhold’s  Demonstration  Prisms 

262,  263 

Weinhold’s  Rotary  Field  Apparatus  399 
Welsbach  Gas  Mantle,  mounted  .  .  244 

Westphal's  Balance .  53 

Wet  and  Dry  Bulb  Hygrometers  .  166 

Whatman  Filter  Paper . 437 

Wheatstone  Bridges  and  Resistance 

Boxes .  360-362 

Wheatstone  Bridges .  366-369 

Wheel  and  Axle .  115 

Whirl,  Electrostatic . 301 

Whirling  Tables . 21,  77,  78 

Whistles,  Galton's . 184 

Whistle  with  Sliding  Piston  ....  183 

Wicks,  Lamp . 452 

Wilson’s  Radio-Electroscope  ....  295 

Wimshurst  Machines .  290,  292 

Wing  Top,  Burner . 420 


PAGE 

Wire,  all  kinds . 311-313 

Wire,  Bent  at  Right  Angles,  Hall  .  248 

Wire  Gauges .  39 

Wire  Guard . 157 

Wireless  Adjustable  Spark  Gaps  .  .  383 

Wireless  Apparatus .  382-384 

Wireless  Condenser .  384 

Wireless  Detectors . 384 

Wireless  Head  Band  Receivers  .  .  384 

Wireless  High  Potential  Condensers.  383 
Wireless  Oscillating  Transformers  383 

Wireless  Receiving  Outfit . 382 

Wireless  Sending  Outfit . 382 

Wireless  Transformers . 383 

Wire  Pentagon,  T.  &  H .  99 

Wire,  Piano . 199 

Wire,  Platinum . 473 

Wires,  Galvanometer . 348 

Witch . 100 

Wollaston’s  Cryophorous . 211 

Wollaston  Steam  Engine . 233 

Wollaston  Wires . 348 

Wooden  Strip  with  Two  Hooks,  T. 

&  H .  115 

Wood  Models  of  Crystals  ....  68 

Wool,  Glass . 447 

Wrench . 405 

Wynne  Burners . 201 


X 

X-Ray  Pictures . 476 

X-Ray  Tube  Protectors . 310 

X-Ray  Tubes . 309 

X-Ray  Tube  Stands . 310 

Xylophone . 185 


Y 

Young’s  Modulus  Apparatus  ...  95 

Y-Pendulum . 194 

Y-Tubes . 490 


Z 

Zinc  and  Carbon  Battery  Connectors  326 

Zinc  Condensers . 425 

Zinc  Wire . 311 

Zoological  Material . 480 

Zoloogy  Microscope  Slides  .  .  462,  463 


GETTY  CENTER  LIBRARY 


3125  00140  3159 


